/* * Copyright (c) 2010 Nicolas George * Copyright (c) 2011 Stefano Sabatini * Copyright (c) 2012 Clément Bœsch * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ /** * @file * API example for audio decoding and filtering * @example doc/examples/filtering_audio.c */ #include #include #include #include #include #include #include #include const char *filter_descr = "aresample=8000,aformat=sample_fmts=s16:channel_layouts=mono"; const char *player = "ffplay -f s16le -ar 8000 -ac 1 -"; static AVFormatContext *fmt_ctx; static AVCodecContext *dec_ctx; AVFilterContext *buffersink_ctx; AVFilterContext *buffersrc_ctx; AVFilterGraph *filter_graph; static int audio_stream_index = -1; static int open_input_file(const char *filename) { int ret; AVCodec *dec; if ((ret = avformat_open_input(&fmt_ctx, filename, NULL, NULL)) < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n"); return ret; } if ((ret = avformat_find_stream_info(fmt_ctx, NULL)) < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n"); return ret; } /* select the audio stream */ ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_AUDIO, -1, -1, &dec, 0); if (ret < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot find a audio stream in the input file\n"); return ret; } audio_stream_index = ret; dec_ctx = fmt_ctx->streams[audio_stream_index]->codec; av_opt_set_int(dec_ctx, "refcounted_frames", 1, 0); /* init the audio decoder */ if ((ret = avcodec_open2(dec_ctx, dec, NULL)) < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot open audio decoder\n"); return ret; } return 0; } static int init_filters(const char *filters_descr) { char args[512]; int ret; AVFilter *abuffersrc = avfilter_get_by_name("abuffer"); AVFilter *abuffersink = avfilter_get_by_name("abuffersink"); AVFilterInOut *outputs = avfilter_inout_alloc(); AVFilterInOut *inputs = avfilter_inout_alloc(); const enum AVSampleFormat out_sample_fmts[] = { AV_SAMPLE_FMT_S16, -1 }; const int64_t out_channel_layouts[] = { AV_CH_LAYOUT_MONO, -1 }; const int out_sample_rates[] = { 8000, -1 }; const AVFilterLink *outlink; AVRational time_base = fmt_ctx->streams[audio_stream_index]->time_base; filter_graph = avfilter_graph_alloc(); /* buffer audio source: the decoded frames from the decoder will be inserted here. */ if (!dec_ctx->channel_layout) dec_ctx->channel_layout = av_get_default_channel_layout(dec_ctx->channels); snprintf(args, sizeof(args), "time_base=%d/%d:sample_rate=%d:sample_fmt=%s:channel_layout=0x%"PRIx64, time_base.num, time_base.den, dec_ctx->sample_rate, av_get_sample_fmt_name(dec_ctx->sample_fmt), dec_ctx->channel_layout); ret = avfilter_graph_create_filter(&buffersrc_ctx, abuffersrc, "in", args, NULL, filter_graph); if (ret < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer source\n"); return ret; } /* buffer audio sink: to terminate the filter chain. */ ret = avfilter_graph_create_filter(&buffersink_ctx, abuffersink, "out", NULL, NULL, filter_graph); if (ret < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer sink\n"); return ret; } ret = av_opt_set_int_list(buffersink_ctx, "sample_fmts", out_sample_fmts, -1, AV_OPT_SEARCH_CHILDREN); if (ret < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot set output sample format\n"); return ret; } ret = av_opt_set_int_list(buffersink_ctx, "channel_layouts", out_channel_layouts, -1, AV_OPT_SEARCH_CHILDREN); if (ret < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot set output channel layout\n"); return ret; } ret = av_opt_set_int_list(buffersink_ctx, "sample_rates", out_sample_rates, -1, AV_OPT_SEARCH_CHILDREN); if (ret < 0) { av_log(NULL, AV_LOG_ERROR, "Cannot set output sample rate\n"); return ret; } /* Endpoints for the filter graph. */ outputs->name = av_strdup("in"); outputs->filter_ctx = buffersrc_ctx; outputs->pad_idx = 0; outputs->next = NULL; inputs->name = av_strdup("out"); inputs->filter_ctx = buffersink_ctx; inputs->pad_idx = 0; inputs->next = NULL; if ((ret = avfilter_graph_parse_ptr(filter_graph, filters_descr, &inputs, &outputs, NULL)) < 0) return ret; if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0) return ret; /* Print summary of the sink buffer * Note: args buffer is reused to store channel layout string */ outlink = buffersink_ctx->inputs[0]; av_get_channel_layout_string(args, sizeof(args), -1, outlink->channel_layout); av_log(NULL, AV_LOG_INFO, "Output: srate:%dHz fmt:%s chlayout:%s\n", (int)outlink->sample_rate, (char *)av_x_if_null(av_get_sample_fmt_name(outlink->format), "?"), args); return 0; } static void print_frame(const AVFrame *frame) { const int n = frame->nb_samples * av_get_channel_layout_nb_channels(av_frame_get_channel_layout(frame)); const uint16_t *p = (uint16_t*)frame->data[0]; const uint16_t *p_end = p + n; while (p < p_end) { fputc(*p & 0xff, stdout); fputc(*p>>8 & 0xff, stdout); p++; } fflush(stdout); } int main(int argc, char **argv) { int ret; AVPacket packet; AVFrame *frame = av_frame_alloc(); AVFrame *filt_frame = av_frame_alloc(); int got_frame; if (!frame || !filt_frame) { perror("Could not allocate frame"); exit(1); } if (argc != 2) { fprintf(stderr, "Usage: %s file | %s\n", argv[0], player); exit(1); } avcodec_register_all(); av_register_all(); avfilter_register_all(); if ((ret = open_input_file(argv[1])) < 0) goto end; if ((ret = init_filters(filter_descr)) < 0) goto end; /* read all packets */ while (1) { if ((ret = av_read_frame(fmt_ctx, &packet)) < 0) break; if (packet.stream_index == audio_stream_index) { avcodec_get_frame_defaults(frame); got_frame = 0; ret = avcodec_decode_audio4(dec_ctx, frame, &got_frame, &packet); if (ret < 0) { av_log(NULL, AV_LOG_ERROR, "Error decoding audio\n"); continue; } if (got_frame) { /* push the audio data from decoded frame into the filtergraph */ if (av_buffersrc_add_frame_flags(buffersrc_ctx, frame, 0) < 0) { av_log(NULL, AV_LOG_ERROR, "Error while feeding the audio filtergraph\n"); break; } /* pull filtered audio from the filtergraph */ while (1) { ret = av_buffersink_get_frame(buffersink_ctx, filt_frame); if(ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) break; if(ret < 0) goto end; print_frame(filt_frame); av_frame_unref(filt_frame); } } } av_free_packet(&packet); } end: avfilter_graph_free(&filter_graph); if (dec_ctx) avcodec_close(dec_ctx); avformat_close_input(&fmt_ctx); av_frame_free(&frame); av_frame_free(&filt_frame); if (ret < 0 && ret != AVERROR_EOF) { char buf[1024]; av_strerror(ret, buf, sizeof(buf)); fprintf(stderr, "Error occurred: %s\n", buf); exit(1); } exit(0); }