[FFmpeg-cvslog] output-example: K&R formatting cosmetics, comment spelling fixes
Diego Biurrun
git at videolan.org
Fri Mar 30 22:33:27 CEST 2012
ffmpeg | branch: master | Diego Biurrun <diego at biurrun.de> | Fri Mar 30 02:27:05 2012 +0200| [afd8a3957bb682d4075a38d56f1f0596634ff72c] | committer: Diego Biurrun
output-example: K&R formatting cosmetics, comment spelling fixes
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=afd8a3957bb682d4075a38d56f1f0596634ff72c
---
libavformat/output-example.c | 197 +++++++++++++++++++++---------------------
1 files changed, 100 insertions(+), 97 deletions(-)
diff --git a/libavformat/output-example.c b/libavformat/output-example.c
index aadd74a..9dc811c 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;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);
More information about the ffmpeg-cvslog
mailing list