mirror of https://git.ffmpeg.org/ffmpeg.git
output-example: K&R formatting cosmetics, comment spelling fixes
This commit is contained in:
Diego Biurrun
parent
93f6d0475f
commit
afd8a3957b
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@ -44,7 +44,7 @@
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#define STREAM_DURATION 5.0
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#define STREAM_FRAME_RATE 25 /* 25 images/s */
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#define STREAM_NB_FRAMES ((int)(STREAM_DURATION * STREAM_FRAME_RATE))
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#define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */
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#define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */
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static int sws_flags = SWS_BICUBIC;
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@ -80,13 +80,13 @@ static AVStream *add_audio_stream(AVFormatContext *oc, enum CodecID codec_id)
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c = st->codec;
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/* put sample parameters */
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c->sample_fmt = AV_SAMPLE_FMT_S16;
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c->bit_rate = 64000;
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c->sample_fmt = AV_SAMPLE_FMT_S16;
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c->bit_rate = 64000;
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c->sample_rate = 44100;
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c->channels = 2;
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c->channels = 2;
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// some formats want stream headers to be separate
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if(oc->oformat->flags & AVFMT_GLOBALHEADER)
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if (oc->oformat->flags & AVFMT_GLOBALHEADER)
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c->flags |= CODEC_FLAG_GLOBAL_HEADER;
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return st;
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@ -105,7 +105,7 @@ static void open_audio(AVFormatContext *oc, AVStream *st)
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}
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/* init signal generator */
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t = 0;
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t = 0;
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tincr = 2 * M_PI * 110.0 / c->sample_rate;
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/* increment frequency by 110 Hz per second */
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tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
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@ -114,23 +114,24 @@ static void open_audio(AVFormatContext *oc, AVStream *st)
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audio_input_frame_size = 10000;
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else
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audio_input_frame_size = c->frame_size;
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samples = av_malloc(audio_input_frame_size * av_get_bytes_per_sample(c->sample_fmt)
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* c->channels);
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samples = av_malloc(audio_input_frame_size *
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av_get_bytes_per_sample(c->sample_fmt) *
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c->channels);
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}
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/* prepare a 16 bit dummy audio frame of 'frame_size' samples and
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'nb_channels' channels */
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/* Prepare a 16 bit dummy audio frame of 'frame_size' samples and
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* 'nb_channels' channels. */
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static void get_audio_frame(int16_t *samples, int frame_size, int nb_channels)
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{
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int j, i, v;
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int16_t *q;
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q = samples;
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for(j=0;j<frame_size;j++) {
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for (j = 0; j < frame_size; j++) {
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v = (int)(sin(t) * 10000);
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for(i = 0; i < nb_channels; i++)
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for (i = 0; i < nb_channels; i++)
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*q++ = v;
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t += tincr;
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t += tincr;
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tincr += tincr2;
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}
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}
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@ -147,17 +148,19 @@ static void write_audio_frame(AVFormatContext *oc, AVStream *st)
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get_audio_frame(samples, audio_input_frame_size, c->channels);
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frame->nb_samples = audio_input_frame_size;
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avcodec_fill_audio_frame(frame, c->channels, c->sample_fmt, (uint8_t *)samples,
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audio_input_frame_size * av_get_bytes_per_sample(c->sample_fmt)
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* c->channels, 1);
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avcodec_fill_audio_frame(frame, c->channels, c->sample_fmt,
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(uint8_t *)samples,
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audio_input_frame_size *
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av_get_bytes_per_sample(c->sample_fmt) *
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c->channels, 1);
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avcodec_encode_audio2(c, &pkt, frame, &got_packet);
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if (!got_packet)
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return;
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pkt.stream_index= st->index;
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pkt.stream_index = st->index;
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/* write the compressed frame in the media file */
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/* Write the compressed frame to the media file. */
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if (av_interleaved_write_frame(oc, &pkt) != 0) {
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fprintf(stderr, "Error while writing audio frame\n");
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exit(1);
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@ -178,7 +181,7 @@ static AVFrame *picture, *tmp_picture;
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static uint8_t *video_outbuf;
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static int frame_count, video_outbuf_size;
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/* add a video output stream */
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/* Add a video output stream. */
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static AVStream *add_video_stream(AVFormatContext *oc, enum CodecID codec_id)
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{
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AVCodecContext *c;
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@ -200,31 +203,31 @@ static AVStream *add_video_stream(AVFormatContext *oc, enum CodecID codec_id)
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c = st->codec;
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/* put sample parameters */
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/* Put sample parameters. */
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c->bit_rate = 400000;
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/* resolution must be a multiple of two */
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c->width = 352;
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c->height = 288;
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/* time base: this is the fundamental unit of time (in seconds) in terms
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of which frame timestamps are represented. for fixed-fps content,
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timebase should be 1/framerate and timestamp increments should be
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identically 1. */
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/* Resolution must be a multiple of two. */
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c->width = 352;
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c->height = 288;
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/* timebase: This is the fundamental unit of time (in seconds) in terms
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* of which frame timestamps are represented. For fixed-fps content,
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* timebase should be 1/framerate and timestamp increments should be
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* identical to 1. */
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c->time_base.den = STREAM_FRAME_RATE;
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c->time_base.num = 1;
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c->gop_size = 12; /* emit one intra frame every twelve frames at most */
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c->pix_fmt = STREAM_PIX_FMT;
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c->gop_size = 12; /* emit one intra frame every twelve frames at most */
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c->pix_fmt = STREAM_PIX_FMT;
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if (c->codec_id == CODEC_ID_MPEG2VIDEO) {
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/* just for testing, we also add B frames */
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c->max_b_frames = 2;
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}
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if (c->codec_id == CODEC_ID_MPEG1VIDEO){
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if (c->codec_id == CODEC_ID_MPEG1VIDEO) {
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/* Needed to avoid using macroblocks in which some coeffs overflow.
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This does not happen with normal video, it just happens here as
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the motion of the chroma plane does not match the luma plane. */
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c->mb_decision=2;
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* This does not happen with normal video, it just happens here as
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* the motion of the chroma plane does not match the luma plane. */
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c->mb_decision = 2;
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}
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// some formats want stream headers to be separate
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if(oc->oformat->flags & AVFMT_GLOBALHEADER)
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/* Some formats want stream headers to be separate. */
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if (oc->oformat->flags & AVFMT_GLOBALHEADER)
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c->flags |= CODEC_FLAG_GLOBAL_HEADER;
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return st;
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@ -239,7 +242,7 @@ static AVFrame *alloc_picture(enum PixelFormat pix_fmt, int width, int height)
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picture = avcodec_alloc_frame();
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if (!picture)
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return NULL;
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size = avpicture_get_size(pix_fmt, width, height);
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size = avpicture_get_size(pix_fmt, width, height);
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picture_buf = av_malloc(size);
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if (!picture_buf) {
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av_free(picture);
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@ -264,26 +267,26 @@ static void open_video(AVFormatContext *oc, AVStream *st)
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video_outbuf = NULL;
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if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
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/* allocate output buffer */
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/* XXX: API change will be done */
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/* buffers passed into lav* can be allocated any way you prefer,
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as long as they're aligned enough for the architecture, and
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they're freed appropriately (such as using av_free for buffers
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allocated with av_malloc) */
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/* Allocate output buffer. */
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/* XXX: API change will be done. */
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/* Buffers passed into lav* can be allocated any way you prefer,
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* as long as they're aligned enough for the architecture, and
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* they're freed appropriately (such as using av_free for buffers
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* allocated with av_malloc). */
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video_outbuf_size = 200000;
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video_outbuf = av_malloc(video_outbuf_size);
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video_outbuf = av_malloc(video_outbuf_size);
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}
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/* allocate the encoded raw picture */
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/* Allocate the encoded raw picture. */
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picture = alloc_picture(c->pix_fmt, c->width, c->height);
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if (!picture) {
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fprintf(stderr, "Could not allocate picture\n");
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exit(1);
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}
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/* if the output format is not YUV420P, then a temporary YUV420P
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picture is needed too. It is then converted to the required
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output format */
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/* If the output format is not YUV420P, then a temporary YUV420P
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* picture is needed too. It is then converted to the required
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* output format. */
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tmp_picture = NULL;
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if (c->pix_fmt != PIX_FMT_YUV420P) {
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tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height);
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@ -294,23 +297,22 @@ static void open_video(AVFormatContext *oc, AVStream *st)
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}
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}
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/* prepare a dummy image */
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static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
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/* Prepare a dummy image. */
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static void fill_yuv_image(AVFrame *pict, int frame_index,
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int width, int height)
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{
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int x, y, i;
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i = frame_index;
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/* Y */
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for(y=0;y<height;y++) {
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for(x=0;x<width;x++) {
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for (y = 0; y < height; y++)
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for (x = 0; x < width; x++)
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pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
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}
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}
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/* Cb and Cr */
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for(y=0;y<height/2;y++) {
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for(x=0;x<width/2;x++) {
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for (y = 0; y < height / 2; y++) {
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for (x = 0; x < width / 2; x++) {
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pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
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pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
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}
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@ -326,13 +328,13 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st)
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c = st->codec;
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if (frame_count >= STREAM_NB_FRAMES) {
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/* no more frame to compress. The codec has a latency of a few
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frames if using B frames, so we get the last frames by
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passing the same picture again */
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/* No more frames to compress. The codec has a latency of a few
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* frames if using B-frames, so we get the last frames by
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* passing the same picture again. */
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} else {
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if (c->pix_fmt != PIX_FMT_YUV420P) {
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/* as we only generate a YUV420P picture, we must convert it
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to the codec pixel format if needed */
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* to the codec pixel format if needed */
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if (img_convert_ctx == NULL) {
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img_convert_ctx = sws_getContext(c->width, c->height,
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PIX_FMT_YUV420P,
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@ -340,7 +342,8 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st)
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c->pix_fmt,
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sws_flags, NULL, NULL, NULL);
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if (img_convert_ctx == NULL) {
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fprintf(stderr, "Cannot initialize the conversion context\n");
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fprintf(stderr,
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"Cannot initialize the conversion context\n");
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exit(1);
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}
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}
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@ -352,36 +355,37 @@ static void write_video_frame(AVFormatContext *oc, AVStream *st)
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}
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}
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if (oc->oformat->flags & AVFMT_RAWPICTURE) {
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/* raw video case. The API will change slightly in the near
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futur for that */
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/* Raw video case - the API will change slightly in the near
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* future for that. */
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AVPacket pkt;
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av_init_packet(&pkt);
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pkt.flags |= AV_PKT_FLAG_KEY;
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pkt.stream_index= st->index;
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pkt.data= (uint8_t *)picture;
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pkt.size= sizeof(AVPicture);
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pkt.flags |= AV_PKT_FLAG_KEY;
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pkt.stream_index = st->index;
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pkt.data = (uint8_t *)picture;
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pkt.size = sizeof(AVPicture);
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ret = av_interleaved_write_frame(oc, &pkt);
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} else {
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/* encode the image */
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out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
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/* if zero size, it means the image was buffered */
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out_size = avcodec_encode_video(c, video_outbuf,
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video_outbuf_size, picture);
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/* If size is zero, it means the image was buffered. */
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if (out_size > 0) {
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AVPacket pkt;
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av_init_packet(&pkt);
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if (c->coded_frame->pts != AV_NOPTS_VALUE)
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pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
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if(c->coded_frame->key_frame)
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pkt.pts = av_rescale_q(c->coded_frame->pts,
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c->time_base, st->time_base);
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if (c->coded_frame->key_frame)
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pkt.flags |= AV_PKT_FLAG_KEY;
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pkt.stream_index= st->index;
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pkt.data= video_outbuf;
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pkt.size= out_size;
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pkt.stream_index = st->index;
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pkt.data = video_outbuf;
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pkt.size = out_size;
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/* write the compressed frame in the media file */
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/* Write the compressed frame to the media file. */
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ret = av_interleaved_write_frame(oc, &pkt);
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} else {
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ret = 0;
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@ -418,7 +422,7 @@ int main(int argc, char **argv)
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double audio_pts, video_pts;
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int i;
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/* initialize libavcodec, and register all codecs and formats */
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/* Initialize libavcodec, and register all codecs and formats. */
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av_register_all();
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if (argc != 2) {
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@ -432,8 +436,7 @@ int main(int argc, char **argv)
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filename = argv[1];
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/* auto detect the output format from the name. default is
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mpeg. */
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/* Autodetect the output format from the name. default is MPEG. */
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fmt = av_guess_format(NULL, filename, NULL);
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if (!fmt) {
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printf("Could not deduce output format from file extension: using MPEG.\n");
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@ -444,7 +447,7 @@ int main(int argc, char **argv)
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return 1;
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}
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/* allocate the output media context */
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/* Allocate the output media context. */
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oc = avformat_alloc_context();
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if (!oc) {
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fprintf(stderr, "Memory error\n");
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@ -453,8 +456,8 @@ int main(int argc, char **argv)
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oc->oformat = fmt;
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snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
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/* add the audio and video streams using the default format codecs
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and initialize the codecs */
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/* Add the audio and video streams using the default format codecs
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* and initialize the codecs. */
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video_st = NULL;
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audio_st = NULL;
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if (fmt->video_codec != CODEC_ID_NONE) {
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@ -464,8 +467,8 @@ int main(int argc, char **argv)
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audio_st = add_audio_stream(oc, fmt->audio_codec);
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}
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/* now that all the parameters are set, we can open the audio and
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video codecs and allocate the necessary encode buffers */
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/* Now that all the parameters are set, we can open the audio and
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* video codecs and allocate the necessary encode buffers. */
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if (video_st)
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open_video(oc, video_st);
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if (audio_st)
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@ -481,18 +484,19 @@ int main(int argc, char **argv)
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}
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}
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/* write the stream header, if any */
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/* Write the stream header, if any. */
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avformat_write_header(oc, NULL);
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for(;;) {
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/* compute current audio and video time */
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for (;;) {
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/* Compute current audio and video time. */
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if (audio_st)
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audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
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else
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audio_pts = 0.0;
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if (video_st)
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video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
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video_pts = (double)video_st->pts.val * video_st->time_base.num /
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video_st->time_base.den;
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else
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video_pts = 0.0;
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@ -508,28 +512,27 @@ int main(int argc, char **argv)
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}
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}
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/* write the trailer, if any. the trailer must be written
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* before you close the CodecContexts open when you wrote the
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* header; otherwise write_trailer may try to use memory that
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* was freed on av_codec_close() */
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/* Write the trailer, if any. The trailer must be written before you
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* close the CodecContexts open when you wrote the header; otherwise
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* av_write_trailer() may try to use memory that was freed on
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* av_codec_close(). */
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av_write_trailer(oc);
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/* close each codec */
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/* Close each codec. */
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if (video_st)
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close_video(oc, video_st);
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if (audio_st)
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close_audio(oc, audio_st);
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/* free the streams */
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for(i = 0; i < oc->nb_streams; i++) {
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/* Free the streams. */
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for (i = 0; i < oc->nb_streams; i++) {
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av_freep(&oc->streams[i]->codec);
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av_freep(&oc->streams[i]);
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}
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if (!(fmt->flags & AVFMT_NOFILE)) {
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/* close the output file */
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if (!(fmt->flags & AVFMT_NOFILE))
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/* Close the output file. */
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avio_close(oc->pb);
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||||
}
|
||||
|
||||
/* free the stream */
|
||||
av_free(oc);
|
||||
|
|
|
|||
Loading…
Reference in New Issue