/*
 * ffmpeg filter configuration
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdint.h>

#include "ffmpeg.h"

#include "libavfilter/avfilter.h"
#include "libavfilter/buffersink.h"
#include "libavfilter/buffersrc.h"

#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/bprint.h"
#include "libavutil/channel_layout.h"
#include "libavutil/display.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "libavutil/pixfmt.h"
#include "libavutil/imgutils.h"
#include "libavutil/samplefmt.h"

// FIXME: YUV420P etc. are actually supported with full color range,
// yet the latter information isn't available here.
static const enum AVPixelFormat *get_compliance_normal_pix_fmts(const AVCodec *codec, const enum AVPixelFormat default_formats[])
{
    static const enum AVPixelFormat mjpeg_formats[] =
        { AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P,
          AV_PIX_FMT_NONE };

    if (!strcmp(codec->name, "mjpeg")) {
        return mjpeg_formats;
    } else {
        return default_formats;
    }
}

static enum AVPixelFormat
choose_pixel_fmt(const AVCodec *codec, enum AVPixelFormat target,
                 int strict_std_compliance)
{
    if (codec && codec->pix_fmts) {
        const enum AVPixelFormat *p = codec->pix_fmts;
        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(target);
        //FIXME: This should check for AV_PIX_FMT_FLAG_ALPHA after PAL8 pixel format without alpha is implemented
        int has_alpha = desc ? desc->nb_components % 2 == 0 : 0;
        enum AVPixelFormat best= AV_PIX_FMT_NONE;

        if (strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL) {
            p = get_compliance_normal_pix_fmts(codec, p);
        }
        for (; *p != AV_PIX_FMT_NONE; p++) {
            best = av_find_best_pix_fmt_of_2(best, *p, target, has_alpha, NULL);
            if (*p == target)
                break;
        }
        if (*p == AV_PIX_FMT_NONE) {
            if (target != AV_PIX_FMT_NONE)
                av_log(NULL, AV_LOG_WARNING,
                       "Incompatible pixel format '%s' for codec '%s', auto-selecting format '%s'\n",
                       av_get_pix_fmt_name(target),
                       codec->name,
                       av_get_pix_fmt_name(best));
            return best;
        }
    }
    return target;
}

/* May return NULL (no pixel format found), a static string or a string
 * backed by the bprint. Nothing has been written to the AVBPrint in case
 * NULL is returned. The AVBPrint provided should be clean. */
static const char *choose_pix_fmts(OutputFilter *ofilter, AVBPrint *bprint)
{
    OutputStream *ost = ofilter->ost;
    AVCodecContext *enc = ost->enc_ctx;
    const AVDictionaryEntry *strict_dict = av_dict_get(ost->encoder_opts, "strict", NULL, 0);
    if (strict_dict)
        // used by choose_pixel_fmt() and below
        av_opt_set(ost->enc_ctx, "strict", strict_dict->value, 0);

     if (ost->keep_pix_fmt) {
        avfilter_graph_set_auto_convert(ofilter->graph->graph,
                                            AVFILTER_AUTO_CONVERT_NONE);
        if (ost->enc_ctx->pix_fmt == AV_PIX_FMT_NONE)
            return NULL;
        return av_get_pix_fmt_name(ost->enc_ctx->pix_fmt);
    }
    if (ost->enc_ctx->pix_fmt != AV_PIX_FMT_NONE) {
        return av_get_pix_fmt_name(choose_pixel_fmt(enc->codec, enc->pix_fmt,
                                                    ost->enc_ctx->strict_std_compliance));
    } else if (enc->codec->pix_fmts) {
        const enum AVPixelFormat *p;

        p = enc->codec->pix_fmts;
        if (ost->enc_ctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL) {
            p = get_compliance_normal_pix_fmts(enc->codec, p);
        }

        for (; *p != AV_PIX_FMT_NONE; p++) {
            const char *name = av_get_pix_fmt_name(*p);
            av_bprintf(bprint, "%s%c", name, p[1] == AV_PIX_FMT_NONE ? '\0' : '|');
        }
        if (!av_bprint_is_complete(bprint))
            report_and_exit(AVERROR(ENOMEM));
        return bprint->str;
    } else
        return NULL;
}

/* Define a function for appending a list of allowed formats
 * to an AVBPrint. If nonempty, the list will have a header. */
#define DEF_CHOOSE_FORMAT(name, type, var, supported_list, none, printf_format, get_name) \
static void choose_ ## name (OutputFilter *ofilter, AVBPrint *bprint)          \
{                                                                              \
    if (ofilter->var == none && !ofilter->supported_list)                      \
        return;                                                                \
    av_bprintf(bprint, #name "=");                                             \
    if (ofilter->var != none) {                                                \
        av_bprintf(bprint, printf_format, get_name(ofilter->var));             \
    } else {                                                                   \
        const type *p;                                                         \
                                                                               \
        for (p = ofilter->supported_list; *p != none; p++) {                   \
            av_bprintf(bprint, printf_format "|", get_name(*p));               \
        }                                                                      \
        if (bprint->len > 0)                                                   \
            bprint->str[--bprint->len] = '\0';                                 \
    }                                                                          \
    av_bprint_chars(bprint, ':', 1);                                           \
}

//DEF_CHOOSE_FORMAT(pix_fmts, enum AVPixelFormat, format, formats, AV_PIX_FMT_NONE,
//                  GET_PIX_FMT_NAME)

DEF_CHOOSE_FORMAT(sample_fmts, enum AVSampleFormat, format, formats,
                  AV_SAMPLE_FMT_NONE, "%s", av_get_sample_fmt_name)

DEF_CHOOSE_FORMAT(sample_rates, int, sample_rate, sample_rates, 0,
                  "%d", )

static void choose_channel_layouts(OutputFilter *ofilter, AVBPrint *bprint)
{
    if (av_channel_layout_check(&ofilter->ch_layout)) {
        av_bprintf(bprint, "channel_layouts=");
        av_channel_layout_describe_bprint(&ofilter->ch_layout, bprint);
    } else if (ofilter->ch_layouts) {
        const AVChannelLayout *p;

        av_bprintf(bprint, "channel_layouts=");
        for (p = ofilter->ch_layouts; p->nb_channels; p++) {
            av_channel_layout_describe_bprint(p, bprint);
            av_bprintf(bprint, "|");
        }
        if (bprint->len > 0)
            bprint->str[--bprint->len] = '\0';
    } else
        return;
    av_bprint_chars(bprint, ':', 1);
}

int init_simple_filtergraph(InputStream *ist, OutputStream *ost)
{
    FilterGraph *fg = av_mallocz(sizeof(*fg));
    OutputFilter *ofilter;
    InputFilter  *ifilter;

    if (!fg)
        report_and_exit(AVERROR(ENOMEM));
    fg->index = nb_filtergraphs;

    ofilter = ALLOC_ARRAY_ELEM(fg->outputs, fg->nb_outputs);
    ofilter->ost    = ost;
    ofilter->graph  = fg;
    ofilter->format = -1;

    ost->filter = ofilter;

    ifilter = ALLOC_ARRAY_ELEM(fg->inputs, fg->nb_inputs);
    ifilter->ist    = ist;
    ifilter->graph  = fg;
    ifilter->format = -1;

    ifilter->frame_queue = av_fifo_alloc2(8, sizeof(AVFrame*), AV_FIFO_FLAG_AUTO_GROW);
    if (!ifilter->frame_queue)
        report_and_exit(AVERROR(ENOMEM));

    GROW_ARRAY(ist->filters, ist->nb_filters);
    ist->filters[ist->nb_filters - 1] = ifilter;

    GROW_ARRAY(filtergraphs, nb_filtergraphs);
    filtergraphs[nb_filtergraphs - 1] = fg;

    return 0;
}

static char *describe_filter_link(FilterGraph *fg, AVFilterInOut *inout, int in)
{
    AVFilterContext *ctx = inout->filter_ctx;
    AVFilterPad *pads = in ? ctx->input_pads  : ctx->output_pads;
    int       nb_pads = in ? ctx->nb_inputs   : ctx->nb_outputs;
    char *res;

    if (nb_pads > 1)
        res = av_strdup(ctx->filter->name);
    else
        res = av_asprintf("%s:%s", ctx->filter->name,
                          avfilter_pad_get_name(pads, inout->pad_idx));
    if (!res)
        report_and_exit(AVERROR(ENOMEM));
    return res;
}

static void init_input_filter(FilterGraph *fg, AVFilterInOut *in)
{
    InputStream *ist = NULL;
    enum AVMediaType type = avfilter_pad_get_type(in->filter_ctx->input_pads, in->pad_idx);
    InputFilter *ifilter;
    int i;

    // TODO: support other filter types
    if (type != AVMEDIA_TYPE_VIDEO && type != AVMEDIA_TYPE_AUDIO) {
        av_log(NULL, AV_LOG_FATAL, "Only video and audio filters supported "
               "currently.\n");
        exit_program(1);
    }

    if (in->name) {
        AVFormatContext *s;
        AVStream       *st = NULL;
        char *p;
        int file_idx = strtol(in->name, &p, 0);

        if (file_idx < 0 || file_idx >= nb_input_files) {
            av_log(NULL, AV_LOG_FATAL, "Invalid file index %d in filtergraph description %s.\n",
                   file_idx, fg->graph_desc);
            exit_program(1);
        }
        s = input_files[file_idx]->ctx;

        for (i = 0; i < s->nb_streams; i++) {
            enum AVMediaType stream_type = s->streams[i]->codecpar->codec_type;
            if (stream_type != type &&
                !(stream_type == AVMEDIA_TYPE_SUBTITLE &&
                  type == AVMEDIA_TYPE_VIDEO /* sub2video hack */))
                continue;
            if (check_stream_specifier(s, s->streams[i], *p == ':' ? p + 1 : p) == 1) {
                st = s->streams[i];
                break;
            }
        }
        if (!st) {
            av_log(NULL, AV_LOG_FATAL, "Stream specifier '%s' in filtergraph description %s "
                   "matches no streams.\n", p, fg->graph_desc);
            exit_program(1);
        }
        ist = input_files[file_idx]->streams[st->index];
        if (ist->user_set_discard == AVDISCARD_ALL) {
            av_log(NULL, AV_LOG_FATAL, "Stream specifier '%s' in filtergraph description %s "
                   "matches a disabled input stream.\n", p, fg->graph_desc);
            exit_program(1);
        }
    } else {
        /* find the first unused stream of corresponding type */
        for (ist = ist_iter(NULL); ist; ist = ist_iter(ist)) {
            if (ist->user_set_discard == AVDISCARD_ALL)
                continue;
            if (ist->dec_ctx->codec_type == type && ist->discard)
                break;
        }
        if (!ist) {
            av_log(NULL, AV_LOG_FATAL, "Cannot find a matching stream for "
                   "unlabeled input pad %d on filter %s\n", in->pad_idx,
                   in->filter_ctx->name);
            exit_program(1);
        }
    }
    av_assert0(ist);

    ist->discard         = 0;
    ist->decoding_needed |= DECODING_FOR_FILTER;
    ist->processing_needed = 1;
    ist->st->discard = AVDISCARD_NONE;

    ifilter = ALLOC_ARRAY_ELEM(fg->inputs, fg->nb_inputs);
    ifilter->ist    = ist;
    ifilter->graph  = fg;
    ifilter->format = -1;
    ifilter->type   = ist->st->codecpar->codec_type;
    ifilter->name   = describe_filter_link(fg, in, 1);

    ifilter->frame_queue = av_fifo_alloc2(8, sizeof(AVFrame*), AV_FIFO_FLAG_AUTO_GROW);
    if (!ifilter->frame_queue)
        report_and_exit(AVERROR(ENOMEM));

    GROW_ARRAY(ist->filters, ist->nb_filters);
    ist->filters[ist->nb_filters - 1] = ifilter;
}

static int read_binary(const char *path, uint8_t **data, int *len)
{
    AVIOContext *io = NULL;
    int64_t fsize;
    int ret;

    *data = NULL;
    *len  = 0;

    ret = avio_open2(&io, path, AVIO_FLAG_READ, &int_cb, NULL);
    if (ret < 0) {
        av_log(NULL, AV_LOG_ERROR, "Cannot open file '%s': %s\n",
               path, av_err2str(ret));
        return ret;
    }

    fsize = avio_size(io);
    if (fsize < 0 || fsize > INT_MAX) {
        av_log(NULL, AV_LOG_ERROR, "Cannot obtain size of file %s\n", path);
        ret = AVERROR(EIO);
        goto fail;
    }

    *data = av_malloc(fsize);
    if (!*data) {
        ret = AVERROR(ENOMEM);
        goto fail;
    }

    ret = avio_read(io, *data, fsize);
    if (ret != fsize) {
        av_log(NULL, AV_LOG_ERROR, "Error reading file %s\n", path);
        ret = ret < 0 ? ret : AVERROR(EIO);
        goto fail;
    }

    *len = fsize;

    ret = 0;
fail:
    avio_close(io);
    if (ret < 0) {
        av_freep(data);
        *len = 0;
    }
    return ret;
}

static int filter_opt_apply(AVFilterContext *f, const char *key, const char *val)
{
    const AVOption *o;
    int ret;

    ret = av_opt_set(f, key, val, AV_OPT_SEARCH_CHILDREN);
    if (ret >= 0)
        return 0;

    if (ret == AVERROR_OPTION_NOT_FOUND && key[0] == '/')
        o = av_opt_find(f, key + 1, NULL, 0, AV_OPT_SEARCH_CHILDREN);
    if (!o)
        goto err_apply;

    // key is a valid option name prefixed with '/'
    // interpret value as a path from which to load the actual option value
    key++;

    if (o->type == AV_OPT_TYPE_BINARY) {
        uint8_t *data;
        int      len;

        ret = read_binary(val, &data, &len);
        if (ret < 0)
            goto err_load;

        ret = av_opt_set_bin(f, key, data, len, AV_OPT_SEARCH_CHILDREN);
        av_freep(&data);
    } else {
        char *data = file_read(val);
        if (!data) {
            ret = AVERROR(EIO);
            goto err_load;
        }

        ret = av_opt_set(f, key, data, AV_OPT_SEARCH_CHILDREN);
        av_freep(&data);
    }
    if (ret < 0)
        goto err_apply;

    return 0;

err_apply:
    av_log(NULL, AV_LOG_ERROR,
           "Error applying option '%s' to filter '%s': %s\n",
           key, f->filter->name, av_err2str(ret));
    return ret;
err_load:
    av_log(NULL, AV_LOG_ERROR,
           "Error loading value for option '%s' from file '%s'\n",
           key, val);
    return ret;
}

static int graph_opts_apply(AVFilterGraphSegment *seg)
{
    for (size_t i = 0; i < seg->nb_chains; i++) {
        AVFilterChain *ch = seg->chains[i];

        for (size_t j = 0; j < ch->nb_filters; j++) {
            AVFilterParams *p = ch->filters[j];
            const AVDictionaryEntry *e = NULL;

            av_assert0(p->filter);

            while ((e = av_dict_iterate(p->opts, e))) {
                int ret = filter_opt_apply(p->filter, e->key, e->value);
                if (ret < 0)
                    return ret;
            }

            av_dict_free(&p->opts);
        }
    }

    return 0;
}

static int graph_parse(AVFilterGraph *graph, const char *desc,
                       AVFilterInOut **inputs, AVFilterInOut **outputs)
{
    AVFilterGraphSegment *seg;
    int ret;

    ret = avfilter_graph_segment_parse(graph, desc, 0, &seg);
    if (ret < 0)
        return ret;

    ret = avfilter_graph_segment_create_filters(seg, 0);
    if (ret < 0)
        goto fail;

    ret = graph_opts_apply(seg);
    if (ret < 0)
        goto fail;

    ret = avfilter_graph_segment_apply(seg, 0, inputs, outputs);

fail:
    avfilter_graph_segment_free(&seg);
    return ret;
}

int init_complex_filtergraph(FilterGraph *fg)
{
    AVFilterInOut *inputs, *outputs, *cur;
    AVFilterGraph *graph;
    int ret = 0;

    /* this graph is only used for determining the kinds of inputs
     * and outputs we have, and is discarded on exit from this function */
    graph = avfilter_graph_alloc();
    if (!graph)
        return AVERROR(ENOMEM);
    graph->nb_threads = 1;

    ret = graph_parse(graph, fg->graph_desc, &inputs, &outputs);
    if (ret < 0)
        goto fail;

    for (cur = inputs; cur; cur = cur->next)
        init_input_filter(fg, cur);

    for (cur = outputs; cur;) {
        OutputFilter *const ofilter = ALLOC_ARRAY_ELEM(fg->outputs, fg->nb_outputs);

        ofilter->graph   = fg;
        ofilter->out_tmp = cur;
        ofilter->type    = avfilter_pad_get_type(cur->filter_ctx->output_pads,
                                                                         cur->pad_idx);
        ofilter->name    = describe_filter_link(fg, cur, 0);
        cur = cur->next;
        ofilter->out_tmp->next = NULL;
    }

fail:
    avfilter_inout_free(&inputs);
    avfilter_graph_free(&graph);
    return ret;
}

static int insert_trim(int64_t start_time, int64_t duration,
                       AVFilterContext **last_filter, int *pad_idx,
                       const char *filter_name)
{
    AVFilterGraph *graph = (*last_filter)->graph;
    AVFilterContext *ctx;
    const AVFilter *trim;
    enum AVMediaType type = avfilter_pad_get_type((*last_filter)->output_pads, *pad_idx);
    const char *name = (type == AVMEDIA_TYPE_VIDEO) ? "trim" : "atrim";
    int ret = 0;

    if (duration == INT64_MAX && start_time == AV_NOPTS_VALUE)
        return 0;

    trim = avfilter_get_by_name(name);
    if (!trim) {
        av_log(NULL, AV_LOG_ERROR, "%s filter not present, cannot limit "
               "recording time.\n", name);
        return AVERROR_FILTER_NOT_FOUND;
    }

    ctx = avfilter_graph_alloc_filter(graph, trim, filter_name);
    if (!ctx)
        return AVERROR(ENOMEM);

    if (duration != INT64_MAX) {
        ret = av_opt_set_int(ctx, "durationi", duration,
                                AV_OPT_SEARCH_CHILDREN);
    }
    if (ret >= 0 && start_time != AV_NOPTS_VALUE) {
        ret = av_opt_set_int(ctx, "starti", start_time,
                                AV_OPT_SEARCH_CHILDREN);
    }
    if (ret < 0) {
        av_log(ctx, AV_LOG_ERROR, "Error configuring the %s filter", name);
        return ret;
    }

    ret = avfilter_init_str(ctx, NULL);
    if (ret < 0)
        return ret;

    ret = avfilter_link(*last_filter, *pad_idx, ctx, 0);
    if (ret < 0)
        return ret;

    *last_filter = ctx;
    *pad_idx     = 0;
    return 0;
}

static int insert_filter(AVFilterContext **last_filter, int *pad_idx,
                         const char *filter_name, const char *args)
{
    AVFilterGraph *graph = (*last_filter)->graph;
    AVFilterContext *ctx;
    int ret;

    ret = avfilter_graph_create_filter(&ctx,
                                       avfilter_get_by_name(filter_name),
                                       filter_name, args, NULL, graph);
    if (ret < 0)
        return ret;

    ret = avfilter_link(*last_filter, *pad_idx, ctx, 0);
    if (ret < 0)
        return ret;

    *last_filter = ctx;
    *pad_idx     = 0;
    return 0;
}

static int configure_output_video_filter(FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out)
{
    OutputStream *ost = ofilter->ost;
    OutputFile    *of = output_files[ost->file_index];
    AVFilterContext *last_filter = out->filter_ctx;
    AVBPrint bprint;
    int pad_idx = out->pad_idx;
    int ret;
    const char *pix_fmts;
    char name[255];

    snprintf(name, sizeof(name), "out_%d_%d", ost->file_index, ost->index);
    ret = avfilter_graph_create_filter(&ofilter->filter,
                                       avfilter_get_by_name("buffersink"),
                                       name, NULL, NULL, fg->graph);

    if (ret < 0)
        return ret;

    if ((ofilter->width || ofilter->height) && ofilter->ost->autoscale) {
        char args[255];
        AVFilterContext *filter;
        const AVDictionaryEntry *e = NULL;

        snprintf(args, sizeof(args), "%d:%d",
                 ofilter->width, ofilter->height);

        while ((e = av_dict_iterate(ost->sws_dict, e))) {
            av_strlcatf(args, sizeof(args), ":%s=%s", e->key, e->value);
        }

        snprintf(name, sizeof(name), "scaler_out_%d_%d",
                 ost->file_index, ost->index);
        if ((ret = avfilter_graph_create_filter(&filter, avfilter_get_by_name("scale"),
                                                name, args, NULL, fg->graph)) < 0)
            return ret;
        if ((ret = avfilter_link(last_filter, pad_idx, filter, 0)) < 0)
            return ret;

        last_filter = filter;
        pad_idx = 0;
    }

    av_bprint_init(&bprint, 0, AV_BPRINT_SIZE_UNLIMITED);
    if ((pix_fmts = choose_pix_fmts(ofilter, &bprint))) {
        AVFilterContext *filter;

        ret = avfilter_graph_create_filter(&filter,
                                           avfilter_get_by_name("format"),
                                           "format", pix_fmts, NULL, fg->graph);
        av_bprint_finalize(&bprint, NULL);
        if (ret < 0)
            return ret;
        if ((ret = avfilter_link(last_filter, pad_idx, filter, 0)) < 0)
            return ret;

        last_filter = filter;
        pad_idx     = 0;
    }

    if (ost->frame_rate.num && 0) {
        AVFilterContext *fps;
        char args[255];

        snprintf(args, sizeof(args), "fps=%d/%d", ost->frame_rate.num,
                 ost->frame_rate.den);
        snprintf(name, sizeof(name), "fps_out_%d_%d",
                 ost->file_index, ost->index);
        ret = avfilter_graph_create_filter(&fps, avfilter_get_by_name("fps"),
                                           name, args, NULL, fg->graph);
        if (ret < 0)
            return ret;

        ret = avfilter_link(last_filter, pad_idx, fps, 0);
        if (ret < 0)
            return ret;
        last_filter = fps;
        pad_idx = 0;
    }

    snprintf(name, sizeof(name), "trim_out_%d_%d",
             ost->file_index, ost->index);
    ret = insert_trim(of->start_time, of->recording_time,
                      &last_filter, &pad_idx, name);
    if (ret < 0)
        return ret;


    if ((ret = avfilter_link(last_filter, pad_idx, ofilter->filter, 0)) < 0)
        return ret;

    return 0;
}

static int configure_output_audio_filter(FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out)
{
    OutputStream *ost = ofilter->ost;
    OutputFile    *of = output_files[ost->file_index];
    AVCodecContext *codec  = ost->enc_ctx;
    AVFilterContext *last_filter = out->filter_ctx;
    int pad_idx = out->pad_idx;
    AVBPrint args;
    char name[255];
    int ret;

    snprintf(name, sizeof(name), "out_%d_%d", ost->file_index, ost->index);
    ret = avfilter_graph_create_filter(&ofilter->filter,
                                       avfilter_get_by_name("abuffersink"),
                                       name, NULL, NULL, fg->graph);
    if (ret < 0)
        return ret;
    if ((ret = av_opt_set_int(ofilter->filter, "all_channel_counts", 1, AV_OPT_SEARCH_CHILDREN)) < 0)
        return ret;

#define AUTO_INSERT_FILTER(opt_name, filter_name, arg) do {                 \
    AVFilterContext *filt_ctx;                                              \
                                                                            \
    av_log(NULL, AV_LOG_INFO, opt_name " is forwarded to lavfi "            \
           "similarly to -af " filter_name "=%s.\n", arg);                  \
                                                                            \
    ret = avfilter_graph_create_filter(&filt_ctx,                           \
                                       avfilter_get_by_name(filter_name),   \
                                       filter_name, arg, NULL, fg->graph);  \
    if (ret < 0)                                                            \
        goto fail;                                                          \
                                                                            \
    ret = avfilter_link(last_filter, pad_idx, filt_ctx, 0);                 \
    if (ret < 0)                                                            \
        goto fail;                                                          \
                                                                            \
    last_filter = filt_ctx;                                                 \
    pad_idx = 0;                                                            \
} while (0)
    av_bprint_init(&args, 0, AV_BPRINT_SIZE_UNLIMITED);
#if FFMPEG_OPT_MAP_CHANNEL
    if (ost->audio_channels_mapped) {
        AVChannelLayout mapped_layout = { 0 };
        int i;
        av_channel_layout_default(&mapped_layout, ost->audio_channels_mapped);
        av_channel_layout_describe_bprint(&mapped_layout, &args);
        for (i = 0; i < ost->audio_channels_mapped; i++)
            if (ost->audio_channels_map[i] != -1)
                av_bprintf(&args, "|c%d=c%d", i, ost->audio_channels_map[i]);

        AUTO_INSERT_FILTER("-map_channel", "pan", args.str);
        av_bprint_clear(&args);
    }
#endif

    if (codec->ch_layout.order == AV_CHANNEL_ORDER_UNSPEC)
        av_channel_layout_default(&codec->ch_layout, codec->ch_layout.nb_channels);

    choose_sample_fmts(ofilter,     &args);
    choose_sample_rates(ofilter,    &args);
    choose_channel_layouts(ofilter, &args);
    if (!av_bprint_is_complete(&args)) {
        ret = AVERROR(ENOMEM);
        goto fail;
    }
    if (args.len) {
        AVFilterContext *format;

        snprintf(name, sizeof(name), "format_out_%d_%d",
                 ost->file_index, ost->index);
        ret = avfilter_graph_create_filter(&format,
                                           avfilter_get_by_name("aformat"),
                                           name, args.str, NULL, fg->graph);
        if (ret < 0)
            goto fail;

        ret = avfilter_link(last_filter, pad_idx, format, 0);
        if (ret < 0)
            goto fail;

        last_filter = format;
        pad_idx = 0;
    }

    if (ost->apad && of->shortest) {
        int i;

        for (i = 0; i < of->nb_streams; i++)
            if (of->streams[i]->st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
                break;

        if (i < of->nb_streams) {
            AUTO_INSERT_FILTER("-apad", "apad", ost->apad);
        }
    }

    snprintf(name, sizeof(name), "trim for output stream %d:%d",
             ost->file_index, ost->index);
    ret = insert_trim(of->start_time, of->recording_time,
                      &last_filter, &pad_idx, name);
    if (ret < 0)
        goto fail;

    if ((ret = avfilter_link(last_filter, pad_idx, ofilter->filter, 0)) < 0)
        goto fail;
fail:
    av_bprint_finalize(&args, NULL);

    return ret;
}

static int configure_output_filter(FilterGraph *fg, OutputFilter *ofilter,
                                   AVFilterInOut *out)
{
    if (!ofilter->ost) {
        av_log(NULL, AV_LOG_FATAL, "Filter %s has an unconnected output\n", ofilter->name);
        exit_program(1);
    }

    switch (avfilter_pad_get_type(out->filter_ctx->output_pads, out->pad_idx)) {
    case AVMEDIA_TYPE_VIDEO: return configure_output_video_filter(fg, ofilter, out);
    case AVMEDIA_TYPE_AUDIO: return configure_output_audio_filter(fg, ofilter, out);
    default: av_assert0(0); return 0;
    }
}

void check_filter_outputs(void)
{
    int i;
    for (i = 0; i < nb_filtergraphs; i++) {
        int n;
        for (n = 0; n < filtergraphs[i]->nb_outputs; n++) {
            OutputFilter *output = filtergraphs[i]->outputs[n];
            if (!output->ost) {
                av_log(NULL, AV_LOG_FATAL, "Filter %s has an unconnected output\n", output->name);
                exit_program(1);
            }
        }
    }
}

static int sub2video_prepare(InputStream *ist, InputFilter *ifilter)
{
    AVFormatContext *avf = input_files[ist->file_index]->ctx;
    int i, w, h;

    /* Compute the size of the canvas for the subtitles stream.
       If the subtitles codecpar has set a size, use it. Otherwise use the
       maximum dimensions of the video streams in the same file. */
    w = ifilter->width;
    h = ifilter->height;
    if (!(w && h)) {
        for (i = 0; i < avf->nb_streams; i++) {
            if (avf->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
                w = FFMAX(w, avf->streams[i]->codecpar->width);
                h = FFMAX(h, avf->streams[i]->codecpar->height);
            }
        }
        if (!(w && h)) {
            w = FFMAX(w, 720);
            h = FFMAX(h, 576);
        }
        av_log(avf, AV_LOG_INFO, "sub2video: using %dx%d canvas\n", w, h);
    }
    ist->sub2video.w = ifilter->width  = w;
    ist->sub2video.h = ifilter->height = h;

    ifilter->width  = ist->dec_ctx->width  ? ist->dec_ctx->width  : ist->sub2video.w;
    ifilter->height = ist->dec_ctx->height ? ist->dec_ctx->height : ist->sub2video.h;

    /* rectangles are AV_PIX_FMT_PAL8, but we have no guarantee that the
       palettes for all rectangles are identical or compatible */
    ifilter->format = AV_PIX_FMT_RGB32;

    ist->sub2video.frame = av_frame_alloc();
    if (!ist->sub2video.frame)
        return AVERROR(ENOMEM);
    ist->sub2video.last_pts = INT64_MIN;
    ist->sub2video.end_pts  = INT64_MIN;

    /* sub2video structure has been (re-)initialized.
       Mark it as such so that the system will be
       initialized with the first received heartbeat. */
    ist->sub2video.initialize = 1;

    return 0;
}

static int configure_input_video_filter(FilterGraph *fg, InputFilter *ifilter,
                                        AVFilterInOut *in)
{
    AVFilterContext *last_filter;
    const AVFilter *buffer_filt = avfilter_get_by_name("buffer");
    const AVPixFmtDescriptor *desc;
    InputStream *ist = ifilter->ist;
    InputFile     *f = input_files[ist->file_index];
    AVRational tb = ist->framerate.num ? av_inv_q(ist->framerate) :
                                         ist->st->time_base;
    AVRational fr = ist->framerate;
    AVRational sar;
    AVBPrint args;
    char name[255];
    int ret, pad_idx = 0;
    int64_t tsoffset = 0;
    AVBufferSrcParameters *par = av_buffersrc_parameters_alloc();

    if (!par)
        return AVERROR(ENOMEM);
    memset(par, 0, sizeof(*par));
    par->format = AV_PIX_FMT_NONE;

    if (ist->dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
        av_log(NULL, AV_LOG_ERROR, "Cannot connect video filter to audio input\n");
        ret = AVERROR(EINVAL);
        goto fail;
    }

    if (!fr.num)
        fr = ist->framerate_guessed;

    if (ist->dec_ctx->codec_type == AVMEDIA_TYPE_SUBTITLE) {
        ret = sub2video_prepare(ist, ifilter);
        if (ret < 0)
            goto fail;
    }

    sar = ifilter->sample_aspect_ratio;
    if(!sar.den)
        sar = (AVRational){0,1};
    av_bprint_init(&args, 0, AV_BPRINT_SIZE_AUTOMATIC);
    av_bprintf(&args,
             "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:"
             "pixel_aspect=%d/%d",
             ifilter->width, ifilter->height, ifilter->format,
             tb.num, tb.den, sar.num, sar.den);
    if (fr.num && fr.den)
        av_bprintf(&args, ":frame_rate=%d/%d", fr.num, fr.den);
    snprintf(name, sizeof(name), "graph %d input from stream %d:%d", fg->index,
             ist->file_index, ist->st->index);


    if ((ret = avfilter_graph_create_filter(&ifilter->filter, buffer_filt, name,
                                            args.str, NULL, fg->graph)) < 0)
        goto fail;
    par->hw_frames_ctx = ifilter->hw_frames_ctx;
    ret = av_buffersrc_parameters_set(ifilter->filter, par);
    if (ret < 0)
        goto fail;
    av_freep(&par);
    last_filter = ifilter->filter;

    desc = av_pix_fmt_desc_get(ifilter->format);
    av_assert0(desc);

    // TODO: insert hwaccel enabled filters like transpose_vaapi into the graph
    if (ist->autorotate && !(desc->flags & AV_PIX_FMT_FLAG_HWACCEL)) {
        int32_t *displaymatrix = ifilter->displaymatrix;
        double theta;

        if (!displaymatrix)
            displaymatrix = (int32_t *)av_stream_get_side_data(ist->st, AV_PKT_DATA_DISPLAYMATRIX, NULL);
        theta = get_rotation(displaymatrix);

        if (fabs(theta - 90) < 1.0) {
            ret = insert_filter(&last_filter, &pad_idx, "transpose",
                                displaymatrix[3] > 0 ? "cclock_flip" : "clock");
        } else if (fabs(theta - 180) < 1.0) {
            if (displaymatrix[0] < 0) {
                ret = insert_filter(&last_filter, &pad_idx, "hflip", NULL);
                if (ret < 0)
                    return ret;
            }
            if (displaymatrix[4] < 0) {
                ret = insert_filter(&last_filter, &pad_idx, "vflip", NULL);
            }
        } else if (fabs(theta - 270) < 1.0) {
            ret = insert_filter(&last_filter, &pad_idx, "transpose",
                                displaymatrix[3] < 0 ? "clock_flip" : "cclock");
        } else if (fabs(theta) > 1.0) {
            char rotate_buf[64];
            snprintf(rotate_buf, sizeof(rotate_buf), "%f*PI/180", theta);
            ret = insert_filter(&last_filter, &pad_idx, "rotate", rotate_buf);
        } else if (fabs(theta) < 1.0) {
            if (displaymatrix && displaymatrix[4] < 0) {
                ret = insert_filter(&last_filter, &pad_idx, "vflip", NULL);
            }
        }
        if (ret < 0)
            return ret;
    }

    snprintf(name, sizeof(name), "trim_in_%d_%d",
             ist->file_index, ist->st->index);
    if (copy_ts) {
        tsoffset = f->start_time == AV_NOPTS_VALUE ? 0 : f->start_time;
        if (!start_at_zero && f->ctx->start_time != AV_NOPTS_VALUE)
            tsoffset += f->ctx->start_time;
    }
    ret = insert_trim(((f->start_time == AV_NOPTS_VALUE) || !f->accurate_seek) ?
                      AV_NOPTS_VALUE : tsoffset, f->recording_time,
                      &last_filter, &pad_idx, name);
    if (ret < 0)
        return ret;

    if ((ret = avfilter_link(last_filter, 0, in->filter_ctx, in->pad_idx)) < 0)
        return ret;
    return 0;
fail:
    av_freep(&par);

    return ret;
}

static int configure_input_audio_filter(FilterGraph *fg, InputFilter *ifilter,
                                        AVFilterInOut *in)
{
    AVFilterContext *last_filter;
    const AVFilter *abuffer_filt = avfilter_get_by_name("abuffer");
    InputStream *ist = ifilter->ist;
    InputFile     *f = input_files[ist->file_index];
    AVBPrint args;
    char name[255];
    int ret, pad_idx = 0;
    int64_t tsoffset = 0;

    if (ist->dec_ctx->codec_type != AVMEDIA_TYPE_AUDIO) {
        av_log(NULL, AV_LOG_ERROR, "Cannot connect audio filter to non audio input\n");
        return AVERROR(EINVAL);
    }

    av_bprint_init(&args, 0, AV_BPRINT_SIZE_AUTOMATIC);
    av_bprintf(&args, "time_base=%d/%d:sample_rate=%d:sample_fmt=%s",
             1, ifilter->sample_rate,
             ifilter->sample_rate,
             av_get_sample_fmt_name(ifilter->format));
    if (av_channel_layout_check(&ifilter->ch_layout) &&
        ifilter->ch_layout.order != AV_CHANNEL_ORDER_UNSPEC) {
        av_bprintf(&args, ":channel_layout=");
        av_channel_layout_describe_bprint(&ifilter->ch_layout, &args);
    } else
        av_bprintf(&args, ":channels=%d", ifilter->ch_layout.nb_channels);
    snprintf(name, sizeof(name), "graph_%d_in_%d_%d", fg->index,
             ist->file_index, ist->st->index);

    if ((ret = avfilter_graph_create_filter(&ifilter->filter, abuffer_filt,
                                            name, args.str, NULL,
                                            fg->graph)) < 0)
        return ret;
    last_filter = ifilter->filter;

#define AUTO_INSERT_FILTER_INPUT(opt_name, filter_name, arg) do {                 \
    AVFilterContext *filt_ctx;                                              \
                                                                            \
    av_log(NULL, AV_LOG_INFO, opt_name " is forwarded to lavfi "            \
           "similarly to -af " filter_name "=%s.\n", arg);                  \
                                                                            \
    snprintf(name, sizeof(name), "graph_%d_%s_in_%d_%d",      \
                fg->index, filter_name, ist->file_index, ist->st->index);   \
    ret = avfilter_graph_create_filter(&filt_ctx,                           \
                                       avfilter_get_by_name(filter_name),   \
                                       name, arg, NULL, fg->graph);         \
    if (ret < 0)                                                            \
        return ret;                                                         \
                                                                            \
    ret = avfilter_link(last_filter, 0, filt_ctx, 0);                       \
    if (ret < 0)                                                            \
        return ret;                                                         \
                                                                            \
    last_filter = filt_ctx;                                                 \
} while (0)

    snprintf(name, sizeof(name), "trim for input stream %d:%d",
             ist->file_index, ist->st->index);
    if (copy_ts) {
        tsoffset = f->start_time == AV_NOPTS_VALUE ? 0 : f->start_time;
        if (!start_at_zero && f->ctx->start_time != AV_NOPTS_VALUE)
            tsoffset += f->ctx->start_time;
    }
    ret = insert_trim(((f->start_time == AV_NOPTS_VALUE) || !f->accurate_seek) ?
                      AV_NOPTS_VALUE : tsoffset, f->recording_time,
                      &last_filter, &pad_idx, name);
    if (ret < 0)
        return ret;

    if ((ret = avfilter_link(last_filter, 0, in->filter_ctx, in->pad_idx)) < 0)
        return ret;

    return 0;
}

static int configure_input_filter(FilterGraph *fg, InputFilter *ifilter,
                                  AVFilterInOut *in)
{
    if (!ifilter->ist->dec) {
        av_log(NULL, AV_LOG_ERROR,
               "No decoder for stream #%d:%d, filtering impossible\n",
               ifilter->ist->file_index, ifilter->ist->st->index);
        return AVERROR_DECODER_NOT_FOUND;
    }
    switch (avfilter_pad_get_type(in->filter_ctx->input_pads, in->pad_idx)) {
    case AVMEDIA_TYPE_VIDEO: return configure_input_video_filter(fg, ifilter, in);
    case AVMEDIA_TYPE_AUDIO: return configure_input_audio_filter(fg, ifilter, in);
    default: av_assert0(0); return 0;
    }
}

static void cleanup_filtergraph(FilterGraph *fg)
{
    int i;
    for (i = 0; i < fg->nb_outputs; i++)
        fg->outputs[i]->filter = (AVFilterContext *)NULL;
    for (i = 0; i < fg->nb_inputs; i++)
        fg->inputs[i]->filter = (AVFilterContext *)NULL;
    avfilter_graph_free(&fg->graph);
}

static int filter_is_buffersrc(const AVFilterContext *f)
{
    return f->nb_inputs == 0 &&
           (!strcmp(f->filter->name, "buffer") ||
            !strcmp(f->filter->name, "abuffer"));
}

static int graph_is_meta(AVFilterGraph *graph)
{
    for (unsigned i = 0; i < graph->nb_filters; i++) {
        const AVFilterContext *f = graph->filters[i];

        /* in addition to filters flagged as meta, also
         * disregard sinks and buffersources (but not other sources,
         * since they introduce data we are not aware of)
         */
        if (!((f->filter->flags & AVFILTER_FLAG_METADATA_ONLY) ||
              f->nb_outputs == 0                               ||
              filter_is_buffersrc(f)))
            return 0;
    }
    return 1;
}

int configure_filtergraph(FilterGraph *fg)
{
    AVFilterInOut *inputs, *outputs, *cur;
    int ret, i, simple = filtergraph_is_simple(fg);
    const char *graph_desc = simple ? fg->outputs[0]->ost->avfilter :
                                      fg->graph_desc;

    cleanup_filtergraph(fg);
    if (!(fg->graph = avfilter_graph_alloc()))
        return AVERROR(ENOMEM);

    if (simple) {
        OutputStream *ost = fg->outputs[0]->ost;

        if (filter_nbthreads) {
            ret = av_opt_set(fg->graph, "threads", filter_nbthreads, 0);
            if (ret < 0)
                goto fail;
        } else {
            const AVDictionaryEntry *e = NULL;
            e = av_dict_get(ost->encoder_opts, "threads", NULL, 0);
            if (e)
                av_opt_set(fg->graph, "threads", e->value, 0);
        }

        if (av_dict_count(ost->sws_dict)) {
            ret = av_dict_get_string(ost->sws_dict,
                                     &fg->graph->scale_sws_opts,
                                     '=', ':');
            if (ret < 0)
                goto fail;
        }

        if (av_dict_count(ost->swr_opts)) {
            char *args;
            ret = av_dict_get_string(ost->swr_opts, &args, '=', ':');
            if (ret < 0)
                goto fail;
            av_opt_set(fg->graph, "aresample_swr_opts", args, 0);
            av_free(args);
        }
    } else {
        fg->graph->nb_threads = filter_complex_nbthreads;
    }

    if ((ret = graph_parse(fg->graph, graph_desc, &inputs, &outputs)) < 0)
        goto fail;

    ret = hw_device_setup_for_filter(fg);
    if (ret < 0)
        goto fail;

    if (simple && (!inputs || inputs->next || !outputs || outputs->next)) {
        const char *num_inputs;
        const char *num_outputs;
        if (!outputs) {
            num_outputs = "0";
        } else if (outputs->next) {
            num_outputs = ">1";
        } else {
            num_outputs = "1";
        }
        if (!inputs) {
            num_inputs = "0";
        } else if (inputs->next) {
            num_inputs = ">1";
        } else {
            num_inputs = "1";
        }
        av_log(NULL, AV_LOG_ERROR, "Simple filtergraph '%s' was expected "
               "to have exactly 1 input and 1 output."
               " However, it had %s input(s) and %s output(s)."
               " Please adjust, or use a complex filtergraph (-filter_complex) instead.\n",
               graph_desc, num_inputs, num_outputs);
        ret = AVERROR(EINVAL);
        goto fail;
    }

    for (cur = inputs, i = 0; cur; cur = cur->next, i++)
        if ((ret = configure_input_filter(fg, fg->inputs[i], cur)) < 0) {
            avfilter_inout_free(&inputs);
            avfilter_inout_free(&outputs);
            goto fail;
        }
    avfilter_inout_free(&inputs);

    for (cur = outputs, i = 0; cur; cur = cur->next, i++)
        configure_output_filter(fg, fg->outputs[i], cur);
    avfilter_inout_free(&outputs);

    if (!auto_conversion_filters)
        avfilter_graph_set_auto_convert(fg->graph, AVFILTER_AUTO_CONVERT_NONE);
    if ((ret = avfilter_graph_config(fg->graph, NULL)) < 0)
        goto fail;

    fg->is_meta = graph_is_meta(fg->graph);

    /* limit the lists of allowed formats to the ones selected, to
     * make sure they stay the same if the filtergraph is reconfigured later */
    for (i = 0; i < fg->nb_outputs; i++) {
        OutputFilter *ofilter = fg->outputs[i];
        AVFilterContext *sink = ofilter->filter;

        ofilter->format = av_buffersink_get_format(sink);

        ofilter->width  = av_buffersink_get_w(sink);
        ofilter->height = av_buffersink_get_h(sink);

        ofilter->sample_rate    = av_buffersink_get_sample_rate(sink);
        av_channel_layout_uninit(&ofilter->ch_layout);
        ret = av_buffersink_get_ch_layout(sink, &ofilter->ch_layout);
        if (ret < 0)
            goto fail;
    }

    fg->reconfiguration = 1;

    for (i = 0; i < fg->nb_outputs; i++) {
        OutputStream *ost = fg->outputs[i]->ost;
        if (ost->enc_ctx->codec_type == AVMEDIA_TYPE_AUDIO &&
            !(ost->enc_ctx->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE))
            av_buffersink_set_frame_size(ost->filter->filter,
                                         ost->enc_ctx->frame_size);
    }

    for (i = 0; i < fg->nb_inputs; i++) {
        AVFrame *tmp;
        while (av_fifo_read(fg->inputs[i]->frame_queue, &tmp, 1) >= 0) {
            ret = av_buffersrc_add_frame(fg->inputs[i]->filter, tmp);
            av_frame_free(&tmp);
            if (ret < 0)
                goto fail;
        }
    }

    /* send the EOFs for the finished inputs */
    for (i = 0; i < fg->nb_inputs; i++) {
        if (fg->inputs[i]->eof) {
            ret = av_buffersrc_add_frame(fg->inputs[i]->filter, NULL);
            if (ret < 0)
                goto fail;
        }
    }

    /* process queued up subtitle packets */
    for (i = 0; i < fg->nb_inputs; i++) {
        InputStream *ist = fg->inputs[i]->ist;
        if (ist->sub2video.sub_queue && ist->sub2video.frame) {
            AVSubtitle tmp;
            while (av_fifo_read(ist->sub2video.sub_queue, &tmp, 1) >= 0) {
                sub2video_update(ist, INT64_MIN, &tmp);
                avsubtitle_free(&tmp);
            }
        }
    }

    return 0;

fail:
    cleanup_filtergraph(fg);
    return ret;
}

int ifilter_parameters_from_frame(InputFilter *ifilter, const AVFrame *frame)
{
    AVFrameSideData *sd;
    int ret;

    av_buffer_unref(&ifilter->hw_frames_ctx);

    ifilter->format = frame->format;

    ifilter->width               = frame->width;
    ifilter->height              = frame->height;
    ifilter->sample_aspect_ratio = frame->sample_aspect_ratio;

    ifilter->sample_rate         = frame->sample_rate;
    ret = av_channel_layout_copy(&ifilter->ch_layout, &frame->ch_layout);
    if (ret < 0)
        return ret;

    av_freep(&ifilter->displaymatrix);
    sd = av_frame_get_side_data(frame, AV_FRAME_DATA_DISPLAYMATRIX);
    if (sd)
        ifilter->displaymatrix = av_memdup(sd->data, sizeof(int32_t) * 9);

    if (frame->hw_frames_ctx) {
        ifilter->hw_frames_ctx = av_buffer_ref(frame->hw_frames_ctx);
        if (!ifilter->hw_frames_ctx)
            return AVERROR(ENOMEM);
    }

    return 0;
}

int filtergraph_is_simple(FilterGraph *fg)
{
    return !fg->graph_desc;
}