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Diffstat (limited to 'doc/examples/muxing.c')
-rw-r--r-- | doc/examples/muxing.c | 613 |
1 files changed, 613 insertions, 0 deletions
diff --git a/doc/examples/muxing.c b/doc/examples/muxing.c new file mode 100644 index 0000000000..fd5028b7c7 --- /dev/null +++ b/doc/examples/muxing.c @@ -0,0 +1,613 @@ +/* + * Copyright (c) 2003 Fabrice Bellard + * + * 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 + * libavformat API example. + * + * Output a media file in any supported libavformat format. The default + * codecs are used. + * @example muxing.c + */ + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <math.h> + +#include <libavutil/avassert.h> +#include <libavutil/channel_layout.h> +#include <libavutil/opt.h> +#include <libavutil/mathematics.h> +#include <libavutil/timestamp.h> +#include <libavformat/avformat.h> +#include <libswscale/swscale.h> +#include <libswresample/swresample.h> + +static int audio_is_eof, video_is_eof; + +#define STREAM_DURATION 10.0 +#define STREAM_FRAME_RATE 25 /* 25 images/s */ +#define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */ + +#define SCALE_FLAGS SWS_BICUBIC + +// a wrapper around a single output AVStream +typedef struct OutputStream { + AVStream *st; + + AVFrame *frame; + AVFrame *tmp_frame; + + float t, tincr, tincr2; + + struct SwsContext *sws_ctx; +} OutputStream; + +static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt) +{ + AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base; + + printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n", + av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base), + av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base), + av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base), + pkt->stream_index); +} + +static int write_frame(AVFormatContext *fmt_ctx, const AVRational *time_base, AVStream *st, AVPacket *pkt) +{ + /* rescale output packet timestamp values from codec to stream timebase */ + av_packet_rescale_ts(pkt, *time_base, st->time_base); + pkt->stream_index = st->index; + + /* Write the compressed frame to the media file. */ + log_packet(fmt_ctx, pkt); + return av_interleaved_write_frame(fmt_ctx, pkt); +} + +/* Add an output stream. */ +static void add_stream(OutputStream *ost, AVFormatContext *oc, + AVCodec **codec, + enum AVCodecID codec_id) +{ + AVCodecContext *c; + + /* find the encoder */ + *codec = avcodec_find_encoder(codec_id); + if (!(*codec)) { + fprintf(stderr, "Could not find encoder for '%s'\n", + avcodec_get_name(codec_id)); + exit(1); + } + + ost->st = avformat_new_stream(oc, *codec); + if (!ost->st) { + fprintf(stderr, "Could not allocate stream\n"); + exit(1); + } + ost->st->id = oc->nb_streams-1; + c = ost->st->codec; + + switch ((*codec)->type) { + case AVMEDIA_TYPE_AUDIO: + c->sample_fmt = (*codec)->sample_fmts ? + (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP; + c->bit_rate = 64000; + c->sample_rate = 44100; + c->channels = 2; + c->channel_layout = AV_CH_LAYOUT_STEREO; + break; + + case AVMEDIA_TYPE_VIDEO: + c->codec_id = codec_id; + + c->bit_rate = 400000; + /* Resolution must be a multiple of two. */ + c->width = 352; + c->height = 288; + /* timebase: This is the fundamental unit of time (in seconds) in terms + * of which frame timestamps are represented. For fixed-fps content, + * timebase should be 1/framerate and timestamp increments should be + * identical to 1. */ + c->time_base.den = STREAM_FRAME_RATE; + c->time_base.num = 1; + c->gop_size = 12; /* emit one intra frame every twelve frames at most */ + c->pix_fmt = STREAM_PIX_FMT; + if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) { + /* just for testing, we also add B frames */ + c->max_b_frames = 2; + } + if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) { + /* Needed to avoid using macroblocks in which some coeffs overflow. + * This does not happen with normal video, it just happens here as + * the motion of the chroma plane does not match the luma plane. */ + c->mb_decision = 2; + } + break; + + default: + break; + } + + /* Some formats want stream headers to be separate. */ + if (oc->oformat->flags & AVFMT_GLOBALHEADER) + c->flags |= CODEC_FLAG_GLOBAL_HEADER; +} + +/**************************************************************/ +/* audio output */ + +int samples_count; + +struct SwrContext *swr_ctx = NULL; + +static void open_audio(AVFormatContext *oc, AVCodec *codec, OutputStream *ost) +{ + AVCodecContext *c; + int ret; + + c = ost->st->codec; + + /* open it */ + ret = avcodec_open2(c, codec, NULL); + if (ret < 0) { + fprintf(stderr, "Could not open audio codec: %s\n", av_err2str(ret)); + exit(1); + } + + /* init signal generator */ + ost->t = 0; + ost->tincr = 2 * M_PI * 110.0 / c->sample_rate; + /* increment frequency by 110 Hz per second */ + ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate; + + ost->frame = av_frame_alloc(); + if (!ost->frame) + exit(1); + + ost->frame->sample_rate = c->sample_rate; + ost->frame->format = AV_SAMPLE_FMT_S16; + ost->frame->channel_layout = c->channel_layout; + + if (c->codec->capabilities & CODEC_CAP_VARIABLE_FRAME_SIZE) + ost->frame->nb_samples = 10000; + else + ost->frame->nb_samples = c->frame_size; + + ost->tmp_frame = av_frame_alloc(); + if (!ost->frame) + exit(1); + + ost->tmp_frame->sample_rate = c->sample_rate; + ost->tmp_frame->format = c->sample_fmt; + ost->tmp_frame->channel_layout = c->channel_layout; + ost->tmp_frame->nb_samples = ost->frame->nb_samples; + + /* create resampler context */ + if (c->sample_fmt != AV_SAMPLE_FMT_S16) { + swr_ctx = swr_alloc(); + if (!swr_ctx) { + fprintf(stderr, "Could not allocate resampler context\n"); + exit(1); + } + + /* set options */ + av_opt_set_int (swr_ctx, "in_channel_count", c->channels, 0); + av_opt_set_int (swr_ctx, "in_sample_rate", c->sample_rate, 0); + av_opt_set_sample_fmt(swr_ctx, "in_sample_fmt", AV_SAMPLE_FMT_S16, 0); + av_opt_set_int (swr_ctx, "out_channel_count", c->channels, 0); + av_opt_set_int (swr_ctx, "out_sample_rate", c->sample_rate, 0); + av_opt_set_sample_fmt(swr_ctx, "out_sample_fmt", c->sample_fmt, 0); + + /* initialize the resampling context */ + if ((ret = swr_init(swr_ctx)) < 0) { + fprintf(stderr, "Failed to initialize the resampling context\n"); + exit(1); + } + } + + ret = av_frame_get_buffer(ost->frame, 0); + if (ret < 0) { + fprintf(stderr, "Could not allocate an audio frame.\n"); + exit(1); + } + ret = av_frame_get_buffer(ost->tmp_frame, 0); + if (ret < 0) { + fprintf(stderr, "Could not allocate an audio frame.\n"); + exit(1); + } +} + +/* Prepare a 16 bit dummy audio frame of 'frame_size' samples and + * 'nb_channels' channels. */ +static void get_audio_frame(OutputStream *ost, AVFrame *frame, int nb_channels) +{ + int j, i, v, ret; + int16_t *q = (int16_t*)frame->data[0]; + + /* when we pass a frame to the encoder, it may keep a reference to it + * internally; + * make sure we do not overwrite it here + */ + ret = av_frame_make_writable(frame); + if (ret < 0) + exit(1); + + for (j = 0; j < frame->nb_samples; j++) { + v = (int)(sin(ost->t) * 10000); + for (i = 0; i < nb_channels; i++) + *q++ = v; + ost->t += ost->tincr; + ost->tincr += ost->tincr2; + } +} + +static void write_audio_frame(AVFormatContext *oc, OutputStream *ost, int flush) +{ + AVCodecContext *c; + AVPacket pkt = { 0 }; // data and size must be 0; + int got_packet, ret; + int dst_nb_samples; + AVFrame *frame; + + av_init_packet(&pkt); + c = ost->st->codec; + + if (!flush) { + get_audio_frame(ost, ost->frame, c->channels); + + /* convert samples from native format to destination codec format, using the resampler */ + if (swr_ctx) { + /* compute destination number of samples */ + dst_nb_samples = av_rescale_rnd(swr_get_delay(swr_ctx, c->sample_rate) + ost->frame->nb_samples, + c->sample_rate, c->sample_rate, AV_ROUND_UP); + av_assert0(dst_nb_samples == ost->frame->nb_samples); + + /* convert to destination format */ + ret = swr_convert(swr_ctx, + ost->tmp_frame->data, dst_nb_samples, + (const uint8_t **)ost->frame->data, ost->frame->nb_samples); + if (ret < 0) { + fprintf(stderr, "Error while converting\n"); + exit(1); + } + frame = ost->tmp_frame; + } else { + dst_nb_samples = ost->frame->nb_samples; + frame = ost->frame; + } + + frame->pts = av_rescale_q(samples_count, (AVRational){1, c->sample_rate}, c->time_base); + samples_count += dst_nb_samples; + } + + ret = avcodec_encode_audio2(c, &pkt, flush ? NULL : frame, &got_packet); + if (ret < 0) { + fprintf(stderr, "Error encoding audio frame: %s\n", av_err2str(ret)); + exit(1); + } + + if (!got_packet) { + if (flush) + audio_is_eof = 1; + + return; + } + + ret = write_frame(oc, &c->time_base, ost->st, &pkt); + if (ret < 0) { + fprintf(stderr, "Error while writing audio frame: %s\n", + av_err2str(ret)); + exit(1); + } +} + +/**************************************************************/ +/* video output */ + +static int frame_count; + +static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height) +{ + AVFrame *picture; + int ret; + + picture = av_frame_alloc(); + if (!picture) + return NULL; + + picture->format = pix_fmt; + picture->width = width; + picture->height = height; + + /* allocate the buffers for the frame data */ + ret = av_frame_get_buffer(picture, 32); + if (ret < 0) { + fprintf(stderr, "Could not allocate frame data.\n"); + exit(1); + } + + return picture; +} + +static void open_video(AVFormatContext *oc, AVCodec *codec, OutputStream *ost) +{ + int ret; + AVCodecContext *c = ost->st->codec; + + /* open the codec */ + ret = avcodec_open2(c, codec, NULL); + if (ret < 0) { + fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret)); + exit(1); + } + + /* allocate and init a re-usable frame */ + ost->frame = alloc_picture(c->pix_fmt, c->width, c->height); + if (!ost->frame) { + fprintf(stderr, "Could not allocate video frame\n"); + exit(1); + } + + /* If the output format is not YUV420P, then a temporary YUV420P + * picture is needed too. It is then converted to the required + * output format. */ + ost->tmp_frame = NULL; + if (c->pix_fmt != AV_PIX_FMT_YUV420P) { + ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height); + if (!ost->tmp_frame) { + fprintf(stderr, "Could not allocate temporary picture\n"); + exit(1); + } + } +} + +/* Prepare a dummy image. */ +static void fill_yuv_image(AVFrame *pict, int frame_index, + int width, int height) +{ + int x, y, i, ret; + + /* when we pass a frame to the encoder, it may keep a reference to it + * internally; + * make sure we do not overwrite it here + */ + ret = av_frame_make_writable(pict); + if (ret < 0) + exit(1); + + i = frame_index; + + /* Y */ + for (y = 0; y < height; y++) + for (x = 0; x < width; x++) + pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3; + + /* Cb and Cr */ + for (y = 0; y < height / 2; y++) { + for (x = 0; x < width / 2; x++) { + pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2; + pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5; + } + } +} + +static void write_video_frame(AVFormatContext *oc, OutputStream *ost, int flush) +{ + int ret; + AVCodecContext *c = ost->st->codec; + + if (!flush) { + if (c->pix_fmt != AV_PIX_FMT_YUV420P) { + /* as we only generate a YUV420P picture, we must convert it + * to the codec pixel format if needed */ + if (!ost->sws_ctx) { + ost->sws_ctx = sws_getContext(c->width, c->height, AV_PIX_FMT_YUV420P, + c->width, c->height, + c->pix_fmt, + SCALE_FLAGS, NULL, NULL, NULL); + if (!ost->sws_ctx) { + fprintf(stderr, + "Could not initialize the conversion context\n"); + exit(1); + } + } + fill_yuv_image(ost->tmp_frame, frame_count, c->width, c->height); + sws_scale(ost->sws_ctx, + (const uint8_t * const *)ost->tmp_frame->data, ost->tmp_frame->linesize, + 0, c->height, ost->frame->data, ost->frame->linesize); + } else { + fill_yuv_image(ost->frame, frame_count, c->width, c->height); + } + } + + if (oc->oformat->flags & AVFMT_RAWPICTURE && !flush) { + /* Raw video case - directly store the picture in the packet */ + AVPacket pkt; + av_init_packet(&pkt); + + pkt.flags |= AV_PKT_FLAG_KEY; + pkt.stream_index = ost->st->index; + pkt.data = (uint8_t *)ost->frame; + pkt.size = sizeof(AVPicture); + + ret = av_interleaved_write_frame(oc, &pkt); + } else { + AVPacket pkt = { 0 }; + int got_packet; + av_init_packet(&pkt); + + /* encode the image */ + ost->frame->pts = frame_count; + ret = avcodec_encode_video2(c, &pkt, flush ? NULL : ost->frame, &got_packet); + if (ret < 0) { + fprintf(stderr, "Error encoding video frame: %s\n", av_err2str(ret)); + exit(1); + } + /* If size is zero, it means the image was buffered. */ + + if (got_packet) { + ret = write_frame(oc, &c->time_base, ost->st, &pkt); + } else { + if (flush) + video_is_eof = 1; + ret = 0; + } + } + + if (ret < 0) { + fprintf(stderr, "Error while writing video frame: %s\n", av_err2str(ret)); + exit(1); + } + frame_count++; +} + +static void close_stream(AVFormatContext *oc, OutputStream *ost) +{ + avcodec_close(ost->st->codec); + av_frame_free(&ost->frame); + av_frame_free(&ost->tmp_frame); + sws_freeContext(ost->sws_ctx); +} + +/**************************************************************/ +/* media file output */ + +int main(int argc, char **argv) +{ + OutputStream video_st = { 0 }, audio_st = { 0 }; + const char *filename; + AVOutputFormat *fmt; + AVFormatContext *oc; + AVCodec *audio_codec, *video_codec; + double audio_time, video_time; + int flush, ret; + int have_video = 0, have_audio = 0; + + /* Initialize libavcodec, and register all codecs and formats. */ + av_register_all(); + + if (argc != 2) { + printf("usage: %s output_file\n" + "API example program to output a media file with libavformat.\n" + "This program generates a synthetic audio and video stream, encodes and\n" + "muxes them into a file named output_file.\n" + "The output format is automatically guessed according to the file extension.\n" + "Raw images can also be output by using '%%d' in the filename.\n" + "\n", argv[0]); + return 1; + } + + filename = argv[1]; + + /* allocate the output media context */ + avformat_alloc_output_context2(&oc, NULL, NULL, filename); + if (!oc) { + printf("Could not deduce output format from file extension: using MPEG.\n"); + avformat_alloc_output_context2(&oc, NULL, "mpeg", filename); + } + if (!oc) + return 1; + + fmt = oc->oformat; + + /* Add the audio and video streams using the default format codecs + * and initialize the codecs. */ + if (fmt->video_codec != AV_CODEC_ID_NONE) { + add_stream(&video_st, oc, &video_codec, fmt->video_codec); + have_video = 1; + } + if (fmt->audio_codec != AV_CODEC_ID_NONE) { + add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec); + have_audio = 1; + } + + /* Now that all the parameters are set, we can open the audio and + * video codecs and allocate the necessary encode buffers. */ + if (have_video) + open_video(oc, video_codec, &video_st); + + if (have_audio) + open_audio(oc, audio_codec, &audio_st); + + av_dump_format(oc, 0, filename, 1); + + /* open the output file, if needed */ + if (!(fmt->flags & AVFMT_NOFILE)) { + ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE); + if (ret < 0) { + fprintf(stderr, "Could not open '%s': %s\n", filename, + av_err2str(ret)); + return 1; + } + } + + /* Write the stream header, if any. */ + ret = avformat_write_header(oc, NULL); + if (ret < 0) { + fprintf(stderr, "Error occurred when opening output file: %s\n", + av_err2str(ret)); + return 1; + } + + flush = 0; + while ((have_video && !video_is_eof) || (have_audio && !audio_is_eof)) { + /* Compute current audio and video time. */ + audio_time = (have_audio && !audio_is_eof) ? audio_st.st->pts.val * av_q2d(audio_st.st->time_base) : INFINITY; + video_time = (have_video && !video_is_eof) ? video_st.st->pts.val * av_q2d(video_st.st->time_base) : INFINITY; + + if (!flush && + (!have_audio || audio_time >= STREAM_DURATION) && + (!have_video || video_time >= STREAM_DURATION)) { + flush = 1; + } + + /* write interleaved audio and video frames */ + if (have_audio && !audio_is_eof && audio_time <= video_time) { + write_audio_frame(oc, &audio_st, flush); + } else if (have_video && !video_is_eof && video_time < audio_time) { + write_video_frame(oc, &video_st, flush); + } + } + + /* Write the trailer, if any. The trailer must be written before you + * close the CodecContexts open when you wrote the header; otherwise + * av_write_trailer() may try to use memory that was freed on + * av_codec_close(). */ + av_write_trailer(oc); + + /* Close each codec. */ + if (have_video) + close_stream(oc, &video_st); + if (have_audio) + close_stream(oc, &audio_st); + + if (!(fmt->flags & AVFMT_NOFILE)) + /* Close the output file. */ + avio_close(oc->pb); + + /* free the stream */ + avformat_free_context(oc); + + return 0; +} |