/* * 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. * * @example output.c * Output a media file in any supported libavformat format. The default * codecs are used. */ #include <stdlib.h> #include <stdio.h> #include <string.h> #include <math.h> #include "libavutil/channel_layout.h" #include "libavutil/mathematics.h" #include "libavutil/opt.h" #include "libavformat/avformat.h" #include "libavresample/avresample.h" #include "libswscale/swscale.h" /* 5 seconds stream duration */ #define STREAM_DURATION 5.0 #define STREAM_FRAME_RATE 25 /* 25 images/s */ #define STREAM_NB_FRAMES ((int)(STREAM_DURATION * STREAM_FRAME_RATE)) #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; AVCodecContext *enc; /* pts of the next frame that will be generated */ int64_t next_pts; AVFrame *frame; AVFrame *tmp_frame; float t, tincr, tincr2; struct SwsContext *sws_ctx; AVAudioResampleContext *avr; } OutputStream; /**************************************************************/ /* audio output */ /* * add an audio output stream */ static void add_audio_stream(OutputStream *ost, AVFormatContext *oc, enum AVCodecID codec_id) { AVCodecContext *c; AVCodec *codec; int ret; /* find the audio encoder */ codec = avcodec_find_encoder(codec_id); if (!codec) { fprintf(stderr, "codec not found\n"); exit(1); } ost->st = avformat_new_stream(oc, NULL); if (!ost->st) { fprintf(stderr, "Could not alloc stream\n"); exit(1); } c = avcodec_alloc_context3(codec); if (!c) { fprintf(stderr, "Could not alloc an encoding context\n"); exit(1); } ost->enc = c; /* put sample parameters */ c->sample_fmt = codec->sample_fmts ? codec->sample_fmts[0] : AV_SAMPLE_FMT_S16; c->sample_rate = codec->supported_samplerates ? codec->supported_samplerates[0] : 44100; c->channel_layout = codec->channel_layouts ? codec->channel_layouts[0] : AV_CH_LAYOUT_STEREO; c->channels = av_get_channel_layout_nb_channels(c->channel_layout); c->bit_rate = 64000; ost->st->time_base = (AVRational){ 1, c->sample_rate }; // some formats want stream headers to be separate if (oc->oformat->flags & AVFMT_GLOBALHEADER) c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER; /* initialize sample format conversion; * to simplify the code, we always pass the data through lavr, even * if the encoder supports the generated format directly -- the price is * some extra data copying; */ ost->avr = avresample_alloc_context(); if (!ost->avr) { fprintf(stderr, "Error allocating the resampling context\n"); exit(1); } av_opt_set_int(ost->avr, "in_sample_fmt", AV_SAMPLE_FMT_S16, 0); av_opt_set_int(ost->avr, "in_sample_rate", 44100, 0); av_opt_set_int(ost->avr, "in_channel_layout", AV_CH_LAYOUT_STEREO, 0); av_opt_set_int(ost->avr, "out_sample_fmt", c->sample_fmt, 0); av_opt_set_int(ost->avr, "out_sample_rate", c->sample_rate, 0); av_opt_set_int(ost->avr, "out_channel_layout", c->channel_layout, 0); ret = avresample_open(ost->avr); if (ret < 0) { fprintf(stderr, "Error opening the resampling context\n"); exit(1); } } static AVFrame *alloc_audio_frame(enum AVSampleFormat sample_fmt, uint64_t channel_layout, int sample_rate, int nb_samples) { AVFrame *frame = av_frame_alloc(); int ret; if (!frame) { fprintf(stderr, "Error allocating an audio frame\n"); exit(1); } frame->format = sample_fmt; frame->channel_layout = channel_layout; frame->sample_rate = sample_rate; frame->nb_samples = nb_samples; if (nb_samples) { ret = av_frame_get_buffer(frame, 0); if (ret < 0) { fprintf(stderr, "Error allocating an audio buffer\n"); exit(1); } } return frame; } static void open_audio(AVFormatContext *oc, OutputStream *ost) { AVCodecContext *c; int nb_samples, ret; c = ost->enc; /* open it */ if (avcodec_open2(c, NULL, NULL) < 0) { fprintf(stderr, "could not open codec\n"); 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; if (c->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE) nb_samples = 10000; else nb_samples = c->frame_size; ost->frame = alloc_audio_frame(c->sample_fmt, c->channel_layout, c->sample_rate, nb_samples); ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, AV_CH_LAYOUT_STEREO, 44100, nb_samples); /* copy the stream parameters to the muxer */ ret = avcodec_parameters_from_context(ost->st->codecpar, c); if (ret < 0) { fprintf(stderr, "Could not copy the stream parameters\n"); exit(1); } } /* Prepare a 16 bit dummy audio frame of 'frame_size' samples and * 'nb_channels' channels. */ static AVFrame *get_audio_frame(OutputStream *ost) { AVFrame *frame = ost->tmp_frame; int j, i, v; int16_t *q = (int16_t*)frame->data[0]; /* check if we want to generate more frames */ if (av_compare_ts(ost->next_pts, ost->enc->time_base, STREAM_DURATION, (AVRational){ 1, 1 }) >= 0) return NULL; for (j = 0; j < frame->nb_samples; j++) { v = (int)(sin(ost->t) * 10000); for (i = 0; i < ost->enc->channels; i++) *q++ = v; ost->t += ost->tincr; ost->tincr += ost->tincr2; } return frame; } /* if a frame is provided, send it to the encoder, otherwise flush the encoder; * return 1 when encoding is finished, 0 otherwise */ static int encode_audio_frame(AVFormatContext *oc, OutputStream *ost, AVFrame *frame) { int ret; ret = avcodec_send_frame(ost->enc, frame); if (ret < 0) { fprintf(stderr, "Error submitting a frame for encoding\n"); exit(1); } while (ret >= 0) { AVPacket pkt = { 0 }; // data and size must be 0; av_init_packet(&pkt); ret = avcodec_receive_packet(ost->enc, &pkt); if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF) { fprintf(stderr, "Error encoding a video frame\n"); exit(1); } else if (ret >= 0) { av_packet_rescale_ts(&pkt, ost->enc->time_base, ost->st->time_base); pkt.stream_index = ost->st->index; /* Write the compressed frame to the media file. */ ret = av_interleaved_write_frame(oc, &pkt); if (ret < 0) { fprintf(stderr, "Error while writing video frame\n"); exit(1); } } } return ret == AVERROR_EOF; } /* * encode one audio frame and send it to the muxer * return 1 when encoding is finished, 0 otherwise */ static int process_audio_stream(AVFormatContext *oc, OutputStream *ost) { AVFrame *frame; int got_output = 0; int ret; frame = get_audio_frame(ost); got_output |= !!frame; /* feed the data to lavr */ if (frame) { ret = avresample_convert(ost->avr, NULL, 0, 0, frame->extended_data, frame->linesize[0], frame->nb_samples); if (ret < 0) { fprintf(stderr, "Error feeding audio data to the resampler\n"); exit(1); } } while ((frame && avresample_available(ost->avr) >= ost->frame->nb_samples) || (!frame && avresample_get_out_samples(ost->avr, 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(ost->frame); if (ret < 0) exit(1); /* the difference between the two avresample calls here is that the * first one just reads the already converted data that is buffered in * the lavr output buffer, while the second one also flushes the * resampler */ if (frame) { ret = avresample_read(ost->avr, ost->frame->extended_data, ost->frame->nb_samples); } else { ret = avresample_convert(ost->avr, ost->frame->extended_data, ost->frame->linesize[0], ost->frame->nb_samples, NULL, 0, 0); } if (ret < 0) { fprintf(stderr, "Error while resampling\n"); exit(1); } else if (frame && ret != ost->frame->nb_samples) { fprintf(stderr, "Too few samples returned from lavr\n"); exit(1); } ost->frame->nb_samples = ret; ost->frame->pts = ost->next_pts; ost->next_pts += ost->frame->nb_samples; got_output |= encode_audio_frame(oc, ost, ret ? ost->frame : NULL); } return !got_output; } /**************************************************************/ /* video output */ /* Add a video output stream. */ static void add_video_stream(OutputStream *ost, AVFormatContext *oc, enum AVCodecID codec_id) { AVCodecContext *c; AVCodec *codec; /* find the video encoder */ codec = avcodec_find_encoder(codec_id); if (!codec) { fprintf(stderr, "codec not found\n"); exit(1); } ost->st = avformat_new_stream(oc, NULL); if (!ost->st) { fprintf(stderr, "Could not alloc stream\n"); exit(1); } c = avcodec_alloc_context3(codec); if (!c) { fprintf(stderr, "Could not alloc an encoding context\n"); exit(1); } ost->enc = c; /* Put sample parameters. */ 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. */ ost->st->time_base = (AVRational){ 1, STREAM_FRAME_RATE }; c->time_base = ost->st->time_base; 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; } /* Some formats want stream headers to be separate. */ if (oc->oformat->flags & AVFMT_GLOBALHEADER) c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER; } 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, OutputStream *ost) { AVCodecContext *c; int ret; c = ost->enc; /* open the codec */ if (avcodec_open2(c, NULL, NULL) < 0) { fprintf(stderr, "could not open codec\n"); exit(1); } /* Allocate the encoded raw picture. */ ost->frame = alloc_picture(c->pix_fmt, c->width, c->height); if (!ost->frame) { fprintf(stderr, "Could not allocate picture\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); } } /* copy the stream parameters to the muxer */ ret = avcodec_parameters_from_context(ost->st->codecpar, c); if (ret < 0) { fprintf(stderr, "Could not copy the stream parameters\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 AVFrame *get_video_frame(OutputStream *ost) { AVCodecContext *c = ost->enc; /* check if we want to generate more frames */ if (av_compare_ts(ost->next_pts, c->time_base, STREAM_DURATION, (AVRational){ 1, 1 }) >= 0) return NULL; 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, "Cannot initialize the conversion context\n"); exit(1); } } fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height); sws_scale(ost->sws_ctx, ost->tmp_frame->data, ost->tmp_frame->linesize, 0, c->height, ost->frame->data, ost->frame->linesize); } else { fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height); } ost->frame->pts = ost->next_pts++; return ost->frame; } /* * encode one video frame and send it to the muxer * return 1 when encoding is finished, 0 otherwise */ static int write_video_frame(AVFormatContext *oc, OutputStream *ost) { int ret; AVCodecContext *c; AVFrame *frame; c = ost->enc; frame = get_video_frame(ost); /* encode the image */ ret = avcodec_send_frame(c, frame); if (ret < 0) { fprintf(stderr, "Error submitting a frame for encoding\n"); exit(1); } while (ret >= 0) { AVPacket pkt = { 0 }; av_init_packet(&pkt); ret = avcodec_receive_packet(c, &pkt); if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF) { fprintf(stderr, "Error encoding a video frame\n"); exit(1); } else if (ret >= 0) { av_packet_rescale_ts(&pkt, c->time_base, ost->st->time_base); pkt.stream_index = ost->st->index; /* Write the compressed frame to the media file. */ ret = av_interleaved_write_frame(oc, &pkt); if (ret < 0) { fprintf(stderr, "Error while writing video frame\n"); exit(1); } } } return ret == AVERROR_EOF; } static void close_stream(AVFormatContext *oc, OutputStream *ost) { avcodec_free_context(&ost->enc); av_frame_free(&ost->frame); av_frame_free(&ost->tmp_frame); sws_freeContext(ost->sws_ctx); avresample_free(&ost->avr); } /**************************************************************/ /* media file output */ int main(int argc, char **argv) { OutputStream video_st = { 0 }, audio_st = { 0 }; const char *filename; AVOutputFormat *fmt; AVFormatContext *oc; int have_video = 0, have_audio = 0; int encode_video = 0, encode_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" "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]; /* Autodetect the output format from the name. default is MPEG. */ fmt = av_guess_format(NULL, filename, NULL); if (!fmt) { printf("Could not deduce output format from file extension: using MPEG.\n"); fmt = av_guess_format("mpeg", NULL, NULL); } if (!fmt) { fprintf(stderr, "Could not find suitable output format\n"); return 1; } /* Allocate the output media context. */ oc = avformat_alloc_context(); if (!oc) { fprintf(stderr, "Memory error\n"); return 1; } oc->oformat = fmt; snprintf(oc->filename, sizeof(oc->filename), "%s", filename); /* Add the audio and video streams using the default format codecs * and initialize the codecs. */ if (fmt->video_codec != AV_CODEC_ID_NONE) { add_video_stream(&video_st, oc, fmt->video_codec); have_video = 1; encode_video = 1; } if (fmt->audio_codec != AV_CODEC_ID_NONE) { add_audio_stream(&audio_st, oc, fmt->audio_codec); have_audio = 1; encode_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_st); if (have_audio) open_audio(oc, &audio_st); av_dump_format(oc, 0, filename, 1); /* open the output file, if needed */ if (!(fmt->flags & AVFMT_NOFILE)) { if (avio_open(&oc->pb, filename, AVIO_FLAG_WRITE) < 0) { fprintf(stderr, "Could not open '%s'\n", filename); return 1; } } /* Write the stream header, if any. */ avformat_write_header(oc, NULL); while (encode_video || encode_audio) { /* select the stream to encode */ if (encode_video && (!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base, audio_st.next_pts, audio_st.enc->time_base) <= 0)) { encode_video = !write_video_frame(oc, &video_st); } else { encode_audio = !process_audio_stream(oc, &audio_st); } } /* 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; }