lavfi: add video buffer sink, and use it in avtools

Also add the public interface libavfilter/buffersink.h.

Based on a commit by Stefano Sabatini.

avconv.c

@@ -50,6 +50,7 @@
 # include "libavfilter/avfilter.h"
 # include "libavfilter/avfiltergraph.h"
 # include "libavfilter/buffersrc.h"
+# include "libavfilter/buffersink.h"
 # include "libavfilter/vsrc_buffer.h"
 
 #if HAVE_SYS_RESOURCE_H
@@ -582,14 +583,25 @@ static void filter_release_buffer(AVFilterBuffer *fb)
     unref_buffer(buf->ist, buf);
 }
 
-static const enum PixelFormat *choose_pixel_fmts(OutputStream *ost)
+static char *choose_pixel_fmts(OutputStream *ost)
 {
     if (ost->st->codec->pix_fmt != PIX_FMT_NONE) {
-        ost->pix_fmts[0] = ost->st->codec->pix_fmt;
-        return ost->pix_fmts;
-    } else if (ost->enc->pix_fmts)
-        return ost->enc->pix_fmts;
-    else
+        return av_strdup(av_get_pix_fmt_name(ost->st->codec->pix_fmt));
+    } else if (ost->enc->pix_fmts) {
+        const enum PixelFormat *p;
+        AVIOContext *s = NULL;
+        uint8_t *ret;
+        int len;
+
+        if (avio_open_dyn_buf(&s) < 0)
+            exit_program(1);
+
+        for (p = ost->enc->pix_fmts; *p != PIX_FMT_NONE; p++)
+            avio_printf(s, "%s:", av_get_pix_fmt_name(*p));
+        len = avio_close_dyn_buf(s, &ret);
+        ret[len - 1] = 0;
+        return ret;
+    } else
         return NULL;
 }
 
@@ -597,9 +609,9 @@ static int configure_video_filters(FilterGraph *fg)
 {
     InputStream  *ist = fg->inputs[0]->ist;
     OutputStream *ost = fg->outputs[0]->ost;
-    AVFilterContext *last_filter, *filter;
+    AVFilterContext *in_filter, *out_filter, *filter;
     AVCodecContext *codec = ost->st->codec;
-    SinkContext sink_ctx = { .pix_fmts = choose_pixel_fmts(ost) };
+    char *pix_fmts;
     AVRational sample_aspect_ratio;
     char args[255];
     int ret;
@@ -621,11 +633,13 @@ static int configure_video_filters(FilterGraph *fg)
                                        "src", args, NULL, fg->graph);
     if (ret < 0)
         return ret;
-    ret = avfilter_graph_create_filter(&fg->outputs[0]->filter, &sink,
-                                       "out", NULL, &sink_ctx, fg->graph);
+    ret = avfilter_graph_create_filter(&fg->outputs[0]->filter,
+                                       avfilter_get_by_name("buffersink"),
+                                       "out", NULL, NULL, fg->graph);
     if (ret < 0)
         return ret;
-    last_filter = fg->inputs[0]->filter;
+    in_filter  = fg->inputs[0]->filter;
+    out_filter = fg->outputs[0]->filter;
 
     if (codec->width || codec->height) {
         snprintf(args, 255, "%d:%d:flags=0x%X",
@@ -635,9 +649,22 @@ static int configure_video_filters(FilterGraph *fg)
         if ((ret = avfilter_graph_create_filter(&filter, avfilter_get_by_name("scale"),
                                                 NULL, args, NULL, fg->graph)) < 0)
             return ret;
-        if ((ret = avfilter_link(last_filter, 0, filter, 0)) < 0)
+        if ((ret = avfilter_link(in_filter, 0, filter, 0)) < 0)
             return ret;
-        last_filter = filter;
+        in_filter = filter;
+    }
+
+    if ((pix_fmts = choose_pixel_fmts(ost))) {
+        if ((ret = avfilter_graph_create_filter(&filter,
+                                                avfilter_get_by_name("format"),
+                                                "format", pix_fmts, NULL,
+                                                fg->graph)) < 0)
+            return ret;
+        if ((ret = avfilter_link(filter, 0, out_filter, 0)) < 0)
+            return ret;
+
+        out_filter = filter;
+        av_freep(&pix_fmts);
     }
 
     snprintf(args, sizeof(args), "flags=0x%X", (unsigned)ost->sws_flags);
@@ -648,19 +675,19 @@ static int configure_video_filters(FilterGraph *fg)
         AVFilterInOut *inputs  = avfilter_inout_alloc();
 
         outputs->name    = av_strdup("in");
-        outputs->filter_ctx = last_filter;
+        outputs->filter_ctx = in_filter;
         outputs->pad_idx = 0;
         outputs->next    = NULL;
 
         inputs->name    = av_strdup("out");
-        inputs->filter_ctx = fg->outputs[0]->filter;
+        inputs->filter_ctx = out_filter;
         inputs->pad_idx = 0;
         inputs->next    = NULL;
 
         if ((ret = avfilter_graph_parse(fg->graph, ost->avfilter, inputs, outputs, NULL)) < 0)
             return ret;
     } else {
-        if ((ret = avfilter_link(last_filter, 0, fg->outputs[0]->filter, 0)) < 0)
+        if ((ret = avfilter_link(in_filter, 0, out_filter, 0)) < 0)
             return ret;
     }
 
@@ -776,33 +803,52 @@ static void init_input_filter(FilterGraph *fg, AVFilterInOut *in)
 
 static int configure_output_filter(FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out)
 {
-    SinkContext  sink_ctx;
+    char *pix_fmts;
     AVCodecContext *codec = ofilter->ost->st->codec;
     AVFilterContext *last_filter = out->filter_ctx;
     int pad_idx = out->pad_idx;
     int ret;
 
-    sink_ctx.pix_fmts = choose_pixel_fmts(ofilter->ost);
 
-    ret = avfilter_graph_create_filter(&ofilter->filter, &sink,
-                                       "out", NULL, &sink_ctx, fg->graph);
+    ret = avfilter_graph_create_filter(&ofilter->filter,
+                                       avfilter_get_by_name("buffersink"),
+                                       "out", NULL, pix_fmts, fg->graph);
     if (ret < 0)
         return ret;
 
     if (codec->width || codec->height) {
         char args[255];
+        AVFilterContext *filter;
+
         snprintf(args, sizeof(args), "%d:%d:flags=0x%X",
                  codec->width,
                  codec->height,
                  (unsigned)ofilter->ost->sws_flags);
-        if ((ret = avfilter_graph_create_filter(&last_filter, avfilter_get_by_name("scale"),
+        if ((ret = avfilter_graph_create_filter(&filter, avfilter_get_by_name("scale"),
                                                 NULL, args, NULL, fg->graph)) < 0)
             return ret;
-        if ((ret = avfilter_link(out->filter_ctx, out->pad_idx, last_filter, 0)) < 0)
+        if ((ret = avfilter_link(last_filter, pad_idx, filter, 0)) < 0)
             return ret;
+
+        last_filter = filter;
         pad_idx = 0;
     }
 
+    if ((pix_fmts = choose_pixel_fmts(ofilter->ost))) {
+        AVFilterContext *filter;
+        if ((ret = avfilter_graph_create_filter(&filter,
+                                                avfilter_get_by_name("format"),
+                                                "format", pix_fmts, 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_freep(&pix_fmts);
+    }
+
     if ((ret = avfilter_link(last_filter, pad_idx, ofilter->filter, 0)) < 0)
         return ret;
 
@@ -1801,7 +1847,7 @@ static int poll_filters(void)
 {
     AVFilterBufferRef *picref;
     AVFrame *filtered_frame = NULL;
-    int i, frame_size, ret;
+    int i, frame_size;
 
     for (i = 0; i < nb_output_streams; i++) {
         OutputStream *ost = output_streams[i];
@@ -1816,13 +1862,11 @@ static int poll_filters(void)
             avcodec_get_frame_defaults(ost->filtered_frame);
         filtered_frame = ost->filtered_frame;
 
-        while (avfilter_poll_frame(ost->filter->filter->inputs[0])) {
-            AVRational ist_pts_tb;
-            if ((ret = get_filtered_video_frame(ost->filter->filter,
-                                                filtered_frame, &picref,
-                                                &ist_pts_tb)) < 0)
-                return ret;
-            filtered_frame->pts = av_rescale_q(picref->pts, ist_pts_tb, AV_TIME_BASE_Q);
+        while (av_buffersink_read(ost->filter->filter, &picref) >= 0) {
+            avfilter_copy_buf_props(filtered_frame, picref);
+            filtered_frame->pts = av_rescale_q(picref->pts,
+                                               ost->filter->filter->inputs[0]->time_base,
+                                               AV_TIME_BASE_Q);
 
             if (of->start_time && filtered_frame->pts < of->start_time)
                 return 0;

avplay.c

@@ -41,6 +41,7 @@
 #if CONFIG_AVFILTER
 # include "libavfilter/avfilter.h"
 # include "libavfilter/avfiltergraph.h"
+# include "libavfilter/buffersink.h"
 #endif
 
 #include "cmdutils.h"
@@ -1708,21 +1709,28 @@ static AVFilter input_filter =
 
 static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const char *vfilters)
 {
-    static const enum PixelFormat pix_fmts[] = { PIX_FMT_YUV420P, PIX_FMT_NONE };
     char sws_flags_str[128];
     int ret;
-    SinkContext sink_ctx = { .pix_fmts = pix_fmts };
-    AVFilterContext *filt_src = NULL, *filt_out = NULL;
+    AVFilterContext *filt_src = NULL, *filt_out = NULL, *filt_format;
     snprintf(sws_flags_str, sizeof(sws_flags_str), "flags=%d", sws_flags);
     graph->scale_sws_opts = av_strdup(sws_flags_str);
 
     if ((ret = avfilter_graph_create_filter(&filt_src, &input_filter, "src",
                                             NULL, is, graph)) < 0)
         return ret;
-    if ((ret = avfilter_graph_create_filter(&filt_out, &sink, "out",
-                                            NULL, &sink_ctx, graph)) < 0)
+    if ((ret = avfilter_graph_create_filter(&filt_out,
+                                            avfilter_get_by_name("buffersink"),
+                                            "out", NULL, NULL, graph)) < 0)
         return ret;
 
+    if ((ret = avfilter_graph_create_filter(&filt_format,
+                                            avfilter_get_by_name("format"),
+                                            "format", "yuv420p", NULL, graph)) < 0)
+        return ret;
+    if ((ret = avfilter_link(filt_format, 0, filt_out, 0)) < 0)
+        return ret;
+
+
     if (vfilters) {
         AVFilterInOut *outputs = avfilter_inout_alloc();
         AVFilterInOut *inputs  = avfilter_inout_alloc();
@@ -1733,14 +1741,14 @@ static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const c
         outputs->next    = NULL;
 
         inputs->name    = av_strdup("out");
-        inputs->filter_ctx = filt_out;
+        inputs->filter_ctx = filt_format;
         inputs->pad_idx = 0;
         inputs->next    = NULL;
 
         if ((ret = avfilter_graph_parse(graph, vfilters, inputs, outputs, NULL)) < 0)
             return ret;
     } else {
-        if ((ret = avfilter_link(filt_src, 0, filt_out, 0)) < 0)
+        if ((ret = avfilter_link(filt_src, 0, filt_format, 0)) < 0)
             return ret;
     }
 
@@ -1796,11 +1804,16 @@ static int video_thread(void *arg)
             last_w = is->video_st->codec->width;
             last_h = is->video_st->codec->height;
         }
-        ret = get_filtered_video_frame(filt_out, frame, &picref, &tb);
+        ret = av_buffersink_read(filt_out, &picref);
         if (picref) {
+            avfilter_copy_buf_props(frame, picref);
+
             pts_int = picref->pts;
+            tb      = filt_out->inputs[0]->time_base;
             pos     = picref->pos;
             frame->opaque = picref;
+
+            ret = 1;
         }
 
         if (ret >= 0 && av_cmp_q(tb, is->video_st->time_base)) {

cmdutils.c

@@ -1021,74 +1021,6 @@ AVDictionary **setup_find_stream_info_opts(AVFormatContext *s,
     return opts;
 }
 
-#if CONFIG_AVFILTER
-
-static int sink_init(AVFilterContext *ctx, const char *args, void *opaque)
-{
-    SinkContext *priv = ctx->priv;
-
-    if (!opaque)
-        return AVERROR(EINVAL);
-    *priv = *(SinkContext *)opaque;
-
-    return 0;
-}
-
-static void null_end_frame(AVFilterLink *inlink) { }
-
-static int sink_query_formats(AVFilterContext *ctx)
-{
-    SinkContext *priv = ctx->priv;
-
-    if (priv->pix_fmts)
-        avfilter_set_common_formats(ctx, avfilter_make_format_list(priv->pix_fmts));
-    else
-        avfilter_default_query_formats(ctx);
-    return 0;
-}
-
-AVFilter sink = {
-    .name      = "sink",
-    .priv_size = sizeof(SinkContext),
-    .init      = sink_init,
-
-    .query_formats = sink_query_formats,
-
-    .inputs    = (AVFilterPad[]) {{ .name          = "default",
-                                    .type          = AVMEDIA_TYPE_VIDEO,
-                                    .end_frame     = null_end_frame,
-                                    .min_perms     = AV_PERM_READ, },
-                                  { .name = NULL }},
-    .outputs   = (AVFilterPad[]) {{ .name = NULL }},
-};
-
-int get_filtered_video_frame(AVFilterContext *ctx, AVFrame *frame,
-                             AVFilterBufferRef **picref_ptr, AVRational *tb)
-{
-    int ret;
-    AVFilterBufferRef *picref;
-
-    if ((ret = avfilter_request_frame(ctx->inputs[0])) < 0)
-        return ret;
-    if (!(picref = ctx->inputs[0]->cur_buf))
-        return AVERROR(ENOENT);
-    *picref_ptr = picref;
-    ctx->inputs[0]->cur_buf = NULL;
-    *tb = ctx->inputs[0]->time_base;
-
-    memcpy(frame->data,     picref->data,     sizeof(frame->data));
-    memcpy(frame->linesize, picref->linesize, sizeof(frame->linesize));
-    frame->interlaced_frame    = picref->video->interlaced;
-    frame->top_field_first     = picref->video->top_field_first;
-    frame->key_frame           = picref->video->key_frame;
-    frame->pict_type           = picref->video->pict_type;
-    frame->sample_aspect_ratio = picref->video->pixel_aspect;
-
-    return 1;
-}
-
-#endif /* CONFIG_AVFILTER */
-
 void *grow_array(void *array, int elem_size, int *size, int new_size)
 {
     if (new_size >= INT_MAX / elem_size) {

cmdutils.h

@@ -367,21 +367,6 @@ int64_t guess_correct_pts(PtsCorrectionContext *ctx, int64_t pts, int64_t dts);
 FILE *get_preset_file(char *filename, size_t filename_size,
                       const char *preset_name, int is_path, const char *codec_name);
 
-typedef struct {
-    const enum PixelFormat *pix_fmts;
-} SinkContext;
-
-extern AVFilter sink;
-
-/**
- * Extract a frame from sink.
- *
- * @return a negative error in case of failure, 1 if one frame has
- * been extracted successfully.
- */
-int get_filtered_video_frame(AVFilterContext *sink, AVFrame *frame,
-                             AVFilterBufferRef **picref, AVRational *pts_tb);
-
 /**
  * Do all the necessary cleanup and abort.
  * This function is implemented in the avtools, not cmdutils.

configure

@@ -1540,7 +1540,7 @@ avfilter_deps="swscale"
 avformat_deps="avcodec"
 
 # programs
-avconv_deps="avcodec avfilter avformat avresample swscale"
+avconv_deps="avcodec avfilter avformat avresample swscale format_filter"
 avplay_deps="avcodec avformat swscale sdl"
 avplay_select="rdft"
 avprobe_deps="avcodec avformat"

doc/filters.texi

@@ -2078,6 +2078,14 @@ will generate a video with a duration of 5.3 seconds, with size
 
 Below is a description of the currently available video sinks.
 
+@section buffersink
+
+Buffer video frames, and make them available to the end of the filter
+graph.
+
+This sink is intended for a programmatic use through the interface defined in
+@file{libavfilter/buffersink.h}.
+
 @section nullsink
 
 Null video sink, do absolutely nothing with the input video. It is

libavfilter/Makefile

@@ -4,6 +4,7 @@ FFLIBS-$(CONFIG_MOVIE_FILTER) += avformat avcodec
 
 HEADERS = avfilter.h                                                    \
           avfiltergraph.h                                               \
+          buffersink.h                                                  \
           buffersrc.h                                                   \
           version.h                                                     \
           vsrc_buffer.h                                                 \
@@ -11,6 +12,7 @@ HEADERS = avfilter.h                                                    \
 OBJS = allfilters.o                                                     \
        avfilter.o                                                       \
        avfiltergraph.o                                                  \
+       buffersink.o                                                     \
        defaults.o                                                       \
        drawutils.o                                                      \
        formats.o                                                        \

libavfilter/allfilters.c

@@ -94,6 +94,10 @@ void avfilter_register_all(void)
         extern AVFilter avfilter_vsrc_buffer;
         avfilter_register(&avfilter_vsrc_buffer);
     }
+    {
+        extern AVFilter avfilter_vsink_buffer;
+        avfilter_register(&avfilter_vsink_buffer);
+    }
     {
         extern AVFilter avfilter_vf_scale;
         avfilter_register(&avfilter_vf_scale);

libavfilter/buffersink.c

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2011 Stefano Sabatini
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * buffer sink
+ */
+
+#include "libavutil/fifo.h"
+
+#include "avfilter.h"
+#include "buffersink.h"
+
+typedef struct {
+    AVFifoBuffer *fifo;          ///< FIFO buffer of video frame references
+} BufferSinkContext;
+
+#define FIFO_INIT_SIZE 8
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    BufferSinkContext *sink = ctx->priv;
+
+    while (sink->fifo && av_fifo_size(sink->fifo)) {
+        AVFilterBufferRef *buf;
+        av_fifo_generic_read(sink->fifo, &buf, sizeof(buf), NULL);
+        avfilter_unref_buffer(buf);
+    }
+    av_fifo_free(sink->fifo);
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    BufferSinkContext *sink = ctx->priv;
+
+    if (!(sink->fifo = av_fifo_alloc(FIFO_INIT_SIZE*sizeof(AVFilterBufferRef*)))) {
+        av_log(ctx, AV_LOG_ERROR, "Failed to allocate fifo\n");
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+static void end_frame(AVFilterLink *link)
+{
+    AVFilterContext   *ctx = link->dst;
+    BufferSinkContext *sink = ctx->priv;
+
+    if (av_fifo_space(sink->fifo) < sizeof(AVFilterBufferRef *) &&
+        (av_fifo_realloc2(sink->fifo, av_fifo_size(sink->fifo) * 2) < 0)) {
+            av_log(ctx, AV_LOG_ERROR, "Error reallocating the FIFO.\n");
+            return;
+    }
+
+    av_fifo_generic_write(sink->fifo, &link->cur_buf, sizeof(link->cur_buf), NULL);
+    link->cur_buf = NULL;
+}
+
+int av_buffersink_read(AVFilterContext *ctx, AVFilterBufferRef **buf)
+{
+    BufferSinkContext *sink = ctx->priv;
+    AVFilterLink      *link = ctx->inputs[0];
+    int ret;
+
+    if (!buf) {
+        if (av_fifo_size(sink->fifo))
+            return av_fifo_size(sink->fifo)/sizeof(*buf);
+        else
+            return avfilter_poll_frame(ctx->inputs[0]);
+    }
+
+    if (!av_fifo_size(sink->fifo) &&
+        (ret = avfilter_request_frame(link)) < 0)
+        return ret;
+
+    if (!av_fifo_size(sink->fifo))
+        return AVERROR(EINVAL);
+
+    av_fifo_generic_read(sink->fifo, buf, sizeof(*buf), NULL);
+
+    return 0;
+}
+
+AVFilter avfilter_vsink_buffer = {
+    .name      = "buffersink",
+    .description = NULL_IF_CONFIG_SMALL("Buffer video frames, and make them available to the end of the filter graph."),
+    .priv_size = sizeof(BufferSinkContext),
+    .init      = init,
+    .uninit    = uninit,
+
+    .inputs    = (AVFilterPad[]) {{ .name          = "default",
+                                    .type          = AVMEDIA_TYPE_VIDEO,
+                                    .end_frame     = end_frame,
+                                    .min_perms     = AV_PERM_READ, },
+                                  { .name = NULL }},
+    .outputs   = (AVFilterPad[]) {{ .name = NULL }},
+};

libavfilter/buffersink.h

@@ -0,0 +1,43 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFILTER_BUFFERSINK_H
+#define AVFILTER_BUFFERSINK_H
+
+/**
+ * @file
+ * memory buffer sink API
+ */
+
+#include "avfilter.h"
+
+/**
+ * Get a buffer with filtered data from sink and put it in buf.
+ *
+ * @param sink pointer to a context of a buffersink AVFilter.
+ * @param buf pointer to the buffer will be written here if buf is non-NULL. buf
+ *            must be freed by the caller using avfilter_unref_buffer().
+ *            Buf may also be NULL to query whether a buffer is ready to be
+ *            output.
+ *
+ * @return >= 0 in case of success, a negative AVERROR code in case of
+ *         failure.
+ */
+int av_buffersink_read(AVFilterContext *sink, AVFilterBufferRef **buf);
+
+#endif /* AVFILTER_BUFFERSINK_H */