diff --git a/libavformat/output-example.c b/libavformat/output-example.c index aadd74a2ad..9dc811ca15 100644 --- a/libavformat/output-example.c +++ b/libavformat/output-example.c @@ -44,7 +44,7 @@ #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 PIX_FMT_YUV420P /* default pix_fmt */ +#define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */ static int sws_flags = SWS_BICUBIC; @@ -80,13 +80,13 @@ static AVStream *add_audio_stream(AVFormatContext *oc, enum CodecID codec_id) c = st->codec; /* put sample parameters */ - c->sample_fmt = AV_SAMPLE_FMT_S16; - c->bit_rate = 64000; + c->sample_fmt = AV_SAMPLE_FMT_S16; + c->bit_rate = 64000; c->sample_rate = 44100; - c->channels = 2; + c->channels = 2; // some formats want stream headers to be separate - if(oc->oformat->flags & AVFMT_GLOBALHEADER) + if (oc->oformat->flags & AVFMT_GLOBALHEADER) c->flags |= CODEC_FLAG_GLOBAL_HEADER; return st; @@ -105,7 +105,7 @@ static void open_audio(AVFormatContext *oc, AVStream *st) } /* init signal generator */ - t = 0; + t = 0; tincr = 2 * M_PI * 110.0 / c->sample_rate; /* increment frequency by 110 Hz per second */ tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate; @@ -114,23 +114,24 @@ static void open_audio(AVFormatContext *oc, AVStream *st) audio_input_frame_size = 10000; else audio_input_frame_size = c->frame_size; - samples = av_malloc(audio_input_frame_size * av_get_bytes_per_sample(c->sample_fmt) - * c->channels); + samples = av_malloc(audio_input_frame_size * + av_get_bytes_per_sample(c->sample_fmt) * + c->channels); } -/* prepare a 16 bit dummy audio frame of 'frame_size' samples and - 'nb_channels' channels */ +/* Prepare a 16 bit dummy audio frame of 'frame_size' samples and + * 'nb_channels' channels. */ static void get_audio_frame(int16_t *samples, int frame_size, int nb_channels) { int j, i, v; int16_t *q; q = samples; - for(j=0;jchannels); frame->nb_samples = audio_input_frame_size; - avcodec_fill_audio_frame(frame, c->channels, c->sample_fmt, (uint8_t *)samples, - audio_input_frame_size * av_get_bytes_per_sample(c->sample_fmt) - * c->channels, 1); + avcodec_fill_audio_frame(frame, c->channels, c->sample_fmt, + (uint8_t *)samples, + audio_input_frame_size * + av_get_bytes_per_sample(c->sample_fmt) * + c->channels, 1); avcodec_encode_audio2(c, &pkt, frame, &got_packet); if (!got_packet) return; - pkt.stream_index= st->index; + pkt.stream_index = st->index; - /* write the compressed frame in the media file */ + /* Write the compressed frame to the media file. */ if (av_interleaved_write_frame(oc, &pkt) != 0) { fprintf(stderr, "Error while writing audio frame\n"); exit(1); @@ -178,7 +181,7 @@ static AVFrame *picture, *tmp_picture; static uint8_t *video_outbuf; static int frame_count, video_outbuf_size; -/* add a video output stream */ +/* Add a video output stream. */ static AVStream *add_video_stream(AVFormatContext *oc, enum CodecID codec_id) { AVCodecContext *c; @@ -200,31 +203,31 @@ static AVStream *add_video_stream(AVFormatContext *oc, enum CodecID codec_id) c = st->codec; - /* put sample parameters */ + /* Put sample parameters. */ c->bit_rate = 400000; - /* resolution must be a multiple of two */ - c->width = 352; - c->height = 288; - /* time base: 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 - identically 1. */ + /* 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; + c->gop_size = 12; /* emit one intra frame every twelve frames at most */ + c->pix_fmt = STREAM_PIX_FMT; if (c->codec_id == CODEC_ID_MPEG2VIDEO) { /* just for testing, we also add B frames */ c->max_b_frames = 2; } - if (c->codec_id == CODEC_ID_MPEG1VIDEO){ + if (c->codec_id == 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; + * 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) + /* Some formats want stream headers to be separate. */ + if (oc->oformat->flags & AVFMT_GLOBALHEADER) c->flags |= CODEC_FLAG_GLOBAL_HEADER; return st; @@ -239,7 +242,7 @@ static AVFrame *alloc_picture(enum PixelFormat pix_fmt, int width, int height) picture = avcodec_alloc_frame(); if (!picture) return NULL; - size = avpicture_get_size(pix_fmt, width, height); + size = avpicture_get_size(pix_fmt, width, height); picture_buf = av_malloc(size); if (!picture_buf) { av_free(picture); @@ -264,26 +267,26 @@ static void open_video(AVFormatContext *oc, AVStream *st) video_outbuf = NULL; if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) { - /* allocate output buffer */ - /* XXX: API change will be done */ - /* buffers passed into lav* can be allocated any way you prefer, - as long as they're aligned enough for the architecture, and - they're freed appropriately (such as using av_free for buffers - allocated with av_malloc) */ + /* Allocate output buffer. */ + /* XXX: API change will be done. */ + /* Buffers passed into lav* can be allocated any way you prefer, + * as long as they're aligned enough for the architecture, and + * they're freed appropriately (such as using av_free for buffers + * allocated with av_malloc). */ video_outbuf_size = 200000; - video_outbuf = av_malloc(video_outbuf_size); + video_outbuf = av_malloc(video_outbuf_size); } - /* allocate the encoded raw picture */ + /* Allocate the encoded raw picture. */ picture = alloc_picture(c->pix_fmt, c->width, c->height); if (!picture) { 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 */ + /* If the output format is not YUV420P, then a temporary YUV420P + * picture is needed too. It is then converted to the required + * output format. */ tmp_picture = NULL; if (c->pix_fmt != PIX_FMT_YUV420P) { tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height); @@ -294,23 +297,22 @@ static void open_video(AVFormatContext *oc, AVStream *st) } } -/* prepare a dummy image */ -static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height) +/* Prepare a dummy image. */ +static void fill_yuv_image(AVFrame *pict, int frame_index, + int width, int height) { int x, y, i; i = frame_index; /* Y */ - for(y=0;ydata[0][y * pict->linesize[0] + x] = x + y + i * 3; - } - } /* Cb and Cr */ - for(y=0;ydata[1][y * pict->linesize[1] + x] = 128 + y + i * 2; pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5; } @@ -326,13 +328,13 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st) c = st->codec; if (frame_count >= STREAM_NB_FRAMES) { - /* no more frame to compress. The codec has a latency of a few - frames if using B frames, so we get the last frames by - passing the same picture again */ + /* No more frames to compress. The codec has a latency of a few + * frames if using B-frames, so we get the last frames by + * passing the same picture again. */ } else { if (c->pix_fmt != PIX_FMT_YUV420P) { /* as we only generate a YUV420P picture, we must convert it - to the codec pixel format if needed */ + * to the codec pixel format if needed */ if (img_convert_ctx == NULL) { img_convert_ctx = sws_getContext(c->width, c->height, PIX_FMT_YUV420P, @@ -340,7 +342,8 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st) c->pix_fmt, sws_flags, NULL, NULL, NULL); if (img_convert_ctx == NULL) { - fprintf(stderr, "Cannot initialize the conversion context\n"); + fprintf(stderr, + "Cannot initialize the conversion context\n"); exit(1); } } @@ -352,36 +355,37 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st) } } - if (oc->oformat->flags & AVFMT_RAWPICTURE) { - /* raw video case. The API will change slightly in the near - futur for that */ + /* Raw video case - the API will change slightly in the near + * future for that. */ AVPacket pkt; av_init_packet(&pkt); - pkt.flags |= AV_PKT_FLAG_KEY; - pkt.stream_index= st->index; - pkt.data= (uint8_t *)picture; - pkt.size= sizeof(AVPicture); + pkt.flags |= AV_PKT_FLAG_KEY; + pkt.stream_index = st->index; + pkt.data = (uint8_t *)picture; + pkt.size = sizeof(AVPicture); ret = av_interleaved_write_frame(oc, &pkt); } else { /* encode the image */ - out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture); - /* if zero size, it means the image was buffered */ + out_size = avcodec_encode_video(c, video_outbuf, + video_outbuf_size, picture); + /* If size is zero, it means the image was buffered. */ if (out_size > 0) { AVPacket pkt; av_init_packet(&pkt); if (c->coded_frame->pts != AV_NOPTS_VALUE) - pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base); - if(c->coded_frame->key_frame) + pkt.pts = av_rescale_q(c->coded_frame->pts, + c->time_base, st->time_base); + if (c->coded_frame->key_frame) pkt.flags |= AV_PKT_FLAG_KEY; - pkt.stream_index= st->index; - pkt.data= video_outbuf; - pkt.size= out_size; + pkt.stream_index = st->index; + pkt.data = video_outbuf; + pkt.size = out_size; - /* write the compressed frame in the media file */ + /* Write the compressed frame to the media file. */ ret = av_interleaved_write_frame(oc, &pkt); } else { ret = 0; @@ -418,7 +422,7 @@ int main(int argc, char **argv) double audio_pts, video_pts; int i; - /* initialize libavcodec, and register all codecs and formats */ + /* Initialize libavcodec, and register all codecs and formats. */ av_register_all(); if (argc != 2) { @@ -432,8 +436,7 @@ int main(int argc, char **argv) filename = argv[1]; - /* auto detect the output format from the name. default is - mpeg. */ + /* 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"); @@ -444,7 +447,7 @@ int main(int argc, char **argv) return 1; } - /* allocate the output media context */ + /* Allocate the output media context. */ oc = avformat_alloc_context(); if (!oc) { fprintf(stderr, "Memory error\n"); @@ -453,8 +456,8 @@ int main(int argc, char **argv) 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 */ + /* Add the audio and video streams using the default format codecs + * and initialize the codecs. */ video_st = NULL; audio_st = NULL; if (fmt->video_codec != CODEC_ID_NONE) { @@ -464,8 +467,8 @@ int main(int argc, char **argv) audio_st = add_audio_stream(oc, fmt->audio_codec); } - /* now that all the parameters are set, we can open the audio and - video codecs and allocate the necessary encode buffers */ + /* Now that all the parameters are set, we can open the audio and + * video codecs and allocate the necessary encode buffers. */ if (video_st) open_video(oc, video_st); if (audio_st) @@ -481,18 +484,19 @@ int main(int argc, char **argv) } } - /* write the stream header, if any */ + /* Write the stream header, if any. */ avformat_write_header(oc, NULL); - for(;;) { - /* compute current audio and video time */ + for (;;) { + /* Compute current audio and video time. */ if (audio_st) audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den; else audio_pts = 0.0; if (video_st) - video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den; + video_pts = (double)video_st->pts.val * video_st->time_base.num / + video_st->time_base.den; else video_pts = 0.0; @@ -508,28 +512,27 @@ int main(int argc, char **argv) } } - /* write the trailer, if any. the trailer must be written - * before you close the CodecContexts open when you wrote the - * header; otherwise write_trailer may try to use memory that - * was freed on av_codec_close() */ + /* 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 */ + /* Close each codec. */ if (video_st) close_video(oc, video_st); if (audio_st) close_audio(oc, audio_st); - /* free the streams */ - for(i = 0; i < oc->nb_streams; i++) { + /* Free the streams. */ + for (i = 0; i < oc->nb_streams; i++) { av_freep(&oc->streams[i]->codec); av_freep(&oc->streams[i]); } - if (!(fmt->flags & AVFMT_NOFILE)) { - /* close the output file */ + if (!(fmt->flags & AVFMT_NOFILE)) + /* Close the output file. */ avio_close(oc->pb); - } /* free the stream */ av_free(oc);