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output-example: K&R formatting cosmetics, comment spelling fixes

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pull/4/merge
Diego Biurrun 13 years ago
parent 93f6d0475f
commit afd8a3957b
1 changed files with 100 additions and 97 deletions
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  1. 197
      libavformat/output-example.c

197
libavformat/output-example.c
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@ -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;j<frame_size;j++) {
for (j = 0; j < frame_size; j++) {
v = (int)(sin(t) * 10000);
for(i = 0; i < nb_channels; i++)
for (i = 0; i < nb_channels; i++)
*q++ = v;
t += tincr;
t += tincr;
tincr += tincr2;
}
}
@ -147,17 +148,19 @@ static void write_audio_frame(AVFormatContext *oc, AVStream *st)
get_audio_frame(samples, audio_input_frame_size, c->channels);
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;y<height;y++) {
for(x=0;x<width;x++) {
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++) {
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;
}
@ -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);

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