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Diffstat (limited to 'doc/examples/transcoding.c')
| -rw-r--r-- | doc/examples/transcoding.c | 597 |
1 files changed, 597 insertions, 0 deletions
diff --git a/doc/examples/transcoding.c b/doc/examples/transcoding.c new file mode 100644 index 0000000000..a8f4210e6e --- /dev/null +++ b/doc/examples/transcoding.c @@ -0,0 +1,597 @@ +/* + * Copyright (c) 2010 Nicolas George + * Copyright (c) 2011 Stefano Sabatini + * Copyright (c) 2014 Andrey Utkin + * + * 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 demuxing, decoding, filtering, encoding and muxing + * @example transcoding.c + */ + +#include <libavcodec/avcodec.h> +#include <libavformat/avformat.h> +#include <libavfilter/avfiltergraph.h> +#include <libavfilter/avcodec.h> +#include <libavfilter/buffersink.h> +#include <libavfilter/buffersrc.h> +#include <libavutil/opt.h> +#include <libavutil/pixdesc.h> + +static AVFormatContext *ifmt_ctx; +static AVFormatContext *ofmt_ctx; +typedef struct FilteringContext { + AVFilterContext *buffersink_ctx; + AVFilterContext *buffersrc_ctx; + AVFilterGraph *filter_graph; +} FilteringContext; +static FilteringContext *filter_ctx; + +static int open_input_file(const char *filename) +{ + int ret; + unsigned int i; + + ifmt_ctx = NULL; + if ((ret = avformat_open_input(&ifmt_ctx, filename, NULL, NULL)) < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n"); + return ret; + } + + if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n"); + return ret; + } + + for (i = 0; i < ifmt_ctx->nb_streams; i++) { + AVStream *stream; + AVCodecContext *codec_ctx; + stream = ifmt_ctx->streams[i]; + codec_ctx = stream->codec; + /* Reencode video & audio and remux subtitles etc. */ + if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO + || codec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) { + /* Open decoder */ + ret = avcodec_open2(codec_ctx, + avcodec_find_decoder(codec_ctx->codec_id), NULL); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Failed to open decoder for stream #%u\n", i); + return ret; + } + } + } + + av_dump_format(ifmt_ctx, 0, filename, 0); + return 0; +} + +static int open_output_file(const char *filename) +{ + AVStream *out_stream; + AVStream *in_stream; + AVCodecContext *dec_ctx, *enc_ctx; + AVCodec *encoder; + int ret; + unsigned int i; + + ofmt_ctx = NULL; + avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, filename); + if (!ofmt_ctx) { + av_log(NULL, AV_LOG_ERROR, "Could not create output context\n"); + return AVERROR_UNKNOWN; + } + + + for (i = 0; i < ifmt_ctx->nb_streams; i++) { + out_stream = avformat_new_stream(ofmt_ctx, NULL); + if (!out_stream) { + av_log(NULL, AV_LOG_ERROR, "Failed allocating output stream\n"); + return AVERROR_UNKNOWN; + } + + in_stream = ifmt_ctx->streams[i]; + dec_ctx = in_stream->codec; + enc_ctx = out_stream->codec; + + if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO + || dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) { + /* in this example, we choose transcoding to same codec */ + encoder = avcodec_find_encoder(dec_ctx->codec_id); + + /* In this example, we transcode to same properties (picture size, + * sample rate etc.). These properties can be changed for output + * streams easily using filters */ + if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) { + enc_ctx->height = dec_ctx->height; + enc_ctx->width = dec_ctx->width; + enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio; + /* take first format from list of supported formats */ + enc_ctx->pix_fmt = encoder->pix_fmts[0]; + /* video time_base can be set to whatever is handy and supported by encoder */ + enc_ctx->time_base = dec_ctx->time_base; + } else { + enc_ctx->sample_rate = dec_ctx->sample_rate; + enc_ctx->channel_layout = dec_ctx->channel_layout; + enc_ctx->channels = av_get_channel_layout_nb_channels(enc_ctx->channel_layout); + /* take first format from list of supported formats */ + enc_ctx->sample_fmt = encoder->sample_fmts[0]; + enc_ctx->time_base = (AVRational){1, enc_ctx->sample_rate}; + } + + /* Third parameter can be used to pass settings to encoder */ + ret = avcodec_open2(enc_ctx, encoder, NULL); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i); + return ret; + } + } else if (dec_ctx->codec_type == AVMEDIA_TYPE_UNKNOWN) { + av_log(NULL, AV_LOG_FATAL, "Elementary stream #%d is of unknown type, cannot proceed\n", i); + return AVERROR_INVALIDDATA; + } else { + /* if this stream must be remuxed */ + ret = avcodec_copy_context(ofmt_ctx->streams[i]->codec, + ifmt_ctx->streams[i]->codec); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Copying stream context failed\n"); + return ret; + } + } + + if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER) + enc_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER; + + } + av_dump_format(ofmt_ctx, 0, filename, 1); + + if (!(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) { + ret = avio_open(&ofmt_ctx->pb, filename, AVIO_FLAG_WRITE); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Could not open output file '%s'", filename); + return ret; + } + } + + /* init muxer, write output file header */ + ret = avformat_write_header(ofmt_ctx, NULL); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Error occurred when opening output file\n"); + return ret; + } + + return 0; +} + +static int init_filter(FilteringContext* fctx, AVCodecContext *dec_ctx, + AVCodecContext *enc_ctx, const char *filter_spec) +{ + char args[512]; + int ret = 0; + AVFilter *buffersrc = NULL; + AVFilter *buffersink = NULL; + AVFilterContext *buffersrc_ctx = NULL; + AVFilterContext *buffersink_ctx = NULL; + AVFilterInOut *outputs = avfilter_inout_alloc(); + AVFilterInOut *inputs = avfilter_inout_alloc(); + AVFilterGraph *filter_graph = avfilter_graph_alloc(); + + if (!outputs || !inputs || !filter_graph) { + ret = AVERROR(ENOMEM); + goto end; + } + + if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) { + buffersrc = avfilter_get_by_name("buffer"); + buffersink = avfilter_get_by_name("buffersink"); + if (!buffersrc || !buffersink) { + av_log(NULL, AV_LOG_ERROR, "filtering source or sink element not found\n"); + ret = AVERROR_UNKNOWN; + goto end; + } + + snprintf(args, sizeof(args), + "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d", + dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt, + dec_ctx->time_base.num, dec_ctx->time_base.den, + dec_ctx->sample_aspect_ratio.num, + dec_ctx->sample_aspect_ratio.den); + + ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in", + args, NULL, filter_graph); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot create buffer source\n"); + goto end; + } + + ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out", + NULL, NULL, filter_graph); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n"); + goto end; + } + + ret = av_opt_set_bin(buffersink_ctx, "pix_fmts", + (uint8_t*)&enc_ctx->pix_fmt, sizeof(enc_ctx->pix_fmt), + AV_OPT_SEARCH_CHILDREN); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot set output pixel format\n"); + goto end; + } + } else if (dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) { + buffersrc = avfilter_get_by_name("abuffer"); + buffersink = avfilter_get_by_name("abuffersink"); + if (!buffersrc || !buffersink) { + av_log(NULL, AV_LOG_ERROR, "filtering source or sink element not found\n"); + ret = AVERROR_UNKNOWN; + goto end; + } + + 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, + dec_ctx->time_base.num, dec_ctx->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, buffersrc, "in", + args, NULL, filter_graph); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer source\n"); + goto end; + } + + ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out", + NULL, NULL, filter_graph); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer sink\n"); + goto end; + } + + ret = av_opt_set_bin(buffersink_ctx, "sample_fmts", + (uint8_t*)&enc_ctx->sample_fmt, sizeof(enc_ctx->sample_fmt), + AV_OPT_SEARCH_CHILDREN); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot set output sample format\n"); + goto end; + } + + ret = av_opt_set_bin(buffersink_ctx, "channel_layouts", + (uint8_t*)&enc_ctx->channel_layout, + sizeof(enc_ctx->channel_layout), AV_OPT_SEARCH_CHILDREN); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot set output channel layout\n"); + goto end; + } + + ret = av_opt_set_bin(buffersink_ctx, "sample_rates", + (uint8_t*)&enc_ctx->sample_rate, sizeof(enc_ctx->sample_rate), + AV_OPT_SEARCH_CHILDREN); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot set output sample rate\n"); + goto end; + } + } else { + ret = AVERROR_UNKNOWN; + goto end; + } + + /* 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 (!outputs->name || !inputs->name) { + ret = AVERROR(ENOMEM); + goto end; + } + + if ((ret = avfilter_graph_parse_ptr(filter_graph, filter_spec, + &inputs, &outputs, NULL)) < 0) + goto end; + + if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0) + goto end; + + /* Fill FilteringContext */ + fctx->buffersrc_ctx = buffersrc_ctx; + fctx->buffersink_ctx = buffersink_ctx; + fctx->filter_graph = filter_graph; + +end: + avfilter_inout_free(&inputs); + avfilter_inout_free(&outputs); + + return ret; +} + +static int init_filters(void) +{ + const char *filter_spec; + unsigned int i; + int ret; + filter_ctx = av_malloc_array(ifmt_ctx->nb_streams, sizeof(*filter_ctx)); + if (!filter_ctx) + return AVERROR(ENOMEM); + + for (i = 0; i < ifmt_ctx->nb_streams; i++) { + filter_ctx[i].buffersrc_ctx = NULL; + filter_ctx[i].buffersink_ctx = NULL; + filter_ctx[i].filter_graph = NULL; + if (!(ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO + || ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)) + continue; + + + if (ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) + filter_spec = "null"; /* passthrough (dummy) filter for video */ + else + filter_spec = "anull"; /* passthrough (dummy) filter for audio */ + ret = init_filter(&filter_ctx[i], ifmt_ctx->streams[i]->codec, + ofmt_ctx->streams[i]->codec, filter_spec); + if (ret) + return ret; + } + return 0; +} + +static int encode_write_frame(AVFrame *filt_frame, unsigned int stream_index, int *got_frame) { + int ret; + int got_frame_local; + AVPacket enc_pkt; + int (*enc_func)(AVCodecContext *, AVPacket *, const AVFrame *, int *) = + (ifmt_ctx->streams[stream_index]->codec->codec_type == + AVMEDIA_TYPE_VIDEO) ? avcodec_encode_video2 : avcodec_encode_audio2; + + if (!got_frame) + got_frame = &got_frame_local; + + av_log(NULL, AV_LOG_INFO, "Encoding frame\n"); + /* encode filtered frame */ + enc_pkt.data = NULL; + enc_pkt.size = 0; + av_init_packet(&enc_pkt); + ret = enc_func(ofmt_ctx->streams[stream_index]->codec, &enc_pkt, + filt_frame, got_frame); + av_frame_free(&filt_frame); + if (ret < 0) + return ret; + if (!(*got_frame)) + return 0; + + /* prepare packet for muxing */ + enc_pkt.stream_index = stream_index; + enc_pkt.dts = av_rescale_q_rnd(enc_pkt.dts, + ofmt_ctx->streams[stream_index]->codec->time_base, + ofmt_ctx->streams[stream_index]->time_base, + AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX); + enc_pkt.pts = av_rescale_q_rnd(enc_pkt.pts, + ofmt_ctx->streams[stream_index]->codec->time_base, + ofmt_ctx->streams[stream_index]->time_base, + AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX); + enc_pkt.duration = av_rescale_q(enc_pkt.duration, + ofmt_ctx->streams[stream_index]->codec->time_base, + ofmt_ctx->streams[stream_index]->time_base); + + av_log(NULL, AV_LOG_DEBUG, "Muxing frame\n"); + /* mux encoded frame */ + ret = av_interleaved_write_frame(ofmt_ctx, &enc_pkt); + return ret; +} + +static int filter_encode_write_frame(AVFrame *frame, unsigned int stream_index) +{ + int ret; + AVFrame *filt_frame; + + av_log(NULL, AV_LOG_INFO, "Pushing decoded frame to filters\n"); + /* push the decoded frame into the filtergraph */ + ret = av_buffersrc_add_frame_flags(filter_ctx[stream_index].buffersrc_ctx, + frame, 0); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Error while feeding the filtergraph\n"); + return ret; + } + + /* pull filtered frames from the filtergraph */ + while (1) { + filt_frame = av_frame_alloc(); + if (!filt_frame) { + ret = AVERROR(ENOMEM); + break; + } + av_log(NULL, AV_LOG_INFO, "Pulling filtered frame from filters\n"); + ret = av_buffersink_get_frame(filter_ctx[stream_index].buffersink_ctx, + filt_frame); + if (ret < 0) { + /* if no more frames for output - returns AVERROR(EAGAIN) + * if flushed and no more frames for output - returns AVERROR_EOF + * rewrite retcode to 0 to show it as normal procedure completion + */ + if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) + ret = 0; + av_frame_free(&filt_frame); + break; + } + + filt_frame->pict_type = AV_PICTURE_TYPE_NONE; + ret = encode_write_frame(filt_frame, stream_index, NULL); + if (ret < 0) + break; + } + + return ret; +} + +static int flush_encoder(unsigned int stream_index) +{ + int ret; + int got_frame; + + if (!(ofmt_ctx->streams[stream_index]->codec->codec->capabilities & + CODEC_CAP_DELAY)) + return 0; + + while (1) { + av_log(NULL, AV_LOG_INFO, "Flushing stream #%u encoder\n", stream_index); + ret = encode_write_frame(NULL, stream_index, &got_frame); + if (ret < 0) + break; + if (!got_frame) + return 0; + } + return ret; +} + +int main(int argc, char **argv) +{ + int ret; + AVPacket packet = { .data = NULL, .size = 0 }; + AVFrame *frame = NULL; + enum AVMediaType type; + unsigned int stream_index; + unsigned int i; + int got_frame; + int (*dec_func)(AVCodecContext *, AVFrame *, int *, const AVPacket *); + + if (argc != 3) { + av_log(NULL, AV_LOG_ERROR, "Usage: %s <input file> <output file>\n", argv[0]); + return 1; + } + + av_register_all(); + avfilter_register_all(); + + if ((ret = open_input_file(argv[1])) < 0) + goto end; + if ((ret = open_output_file(argv[2])) < 0) + goto end; + if ((ret = init_filters()) < 0) + goto end; + + /* read all packets */ + while (1) { + if ((ret = av_read_frame(ifmt_ctx, &packet)) < 0) + break; + stream_index = packet.stream_index; + type = ifmt_ctx->streams[packet.stream_index]->codec->codec_type; + av_log(NULL, AV_LOG_DEBUG, "Demuxer gave frame of stream_index %u\n", + stream_index); + + if (filter_ctx[stream_index].filter_graph) { + av_log(NULL, AV_LOG_DEBUG, "Going to reencode&filter the frame\n"); + frame = av_frame_alloc(); + if (!frame) { + ret = AVERROR(ENOMEM); + break; + } + packet.dts = av_rescale_q_rnd(packet.dts, + ifmt_ctx->streams[stream_index]->time_base, + ifmt_ctx->streams[stream_index]->codec->time_base, + AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX); + packet.pts = av_rescale_q_rnd(packet.pts, + ifmt_ctx->streams[stream_index]->time_base, + ifmt_ctx->streams[stream_index]->codec->time_base, + AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX); + dec_func = (type == AVMEDIA_TYPE_VIDEO) ? avcodec_decode_video2 : + avcodec_decode_audio4; + ret = dec_func(ifmt_ctx->streams[stream_index]->codec, frame, + &got_frame, &packet); + if (ret < 0) { + av_frame_free(&frame); + av_log(NULL, AV_LOG_ERROR, "Decoding failed\n"); + break; + } + + if (got_frame) { + frame->pts = av_frame_get_best_effort_timestamp(frame); + ret = filter_encode_write_frame(frame, stream_index); + av_frame_free(&frame); + if (ret < 0) + goto end; + } else { + av_frame_free(&frame); + } + } else { + /* remux this frame without reencoding */ + packet.dts = av_rescale_q_rnd(packet.dts, + ifmt_ctx->streams[stream_index]->time_base, + ofmt_ctx->streams[stream_index]->time_base, + AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX); + packet.pts = av_rescale_q_rnd(packet.pts, + ifmt_ctx->streams[stream_index]->time_base, + ofmt_ctx->streams[stream_index]->time_base, + AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX); + + ret = av_interleaved_write_frame(ofmt_ctx, &packet); + if (ret < 0) + goto end; + } + av_free_packet(&packet); + } + + /* flush filters and encoders */ + for (i = 0; i < ifmt_ctx->nb_streams; i++) { + /* flush filter */ + if (!filter_ctx[i].filter_graph) + continue; + ret = filter_encode_write_frame(NULL, i); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Flushing filter failed\n"); + goto end; + } + + /* flush encoder */ + ret = flush_encoder(i); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Flushing encoder failed\n"); + goto end; + } + } + + av_write_trailer(ofmt_ctx); +end: + av_free_packet(&packet); + av_frame_free(&frame); + for (i = 0; i < ifmt_ctx->nb_streams; i++) { + avcodec_close(ifmt_ctx->streams[i]->codec); + if (ofmt_ctx && ofmt_ctx->nb_streams > i && ofmt_ctx->streams[i] && ofmt_ctx->streams[i]->codec) + avcodec_close(ofmt_ctx->streams[i]->codec); + if (filter_ctx && filter_ctx[i].filter_graph) + avfilter_graph_free(&filter_ctx[i].filter_graph); + } + av_free(filter_ctx); + avformat_close_input(&ifmt_ctx); + if (ofmt_ctx && !(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) + avio_close(ofmt_ctx->pb); + avformat_free_context(ofmt_ctx); + + if (ret < 0) + av_log(NULL, AV_LOG_ERROR, "Error occurred: %s\n", av_err2str(ret)); + + return ret ? 1 : 0; +} |