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| author | Michael Niedermayer <michaelni@gmx.at> | 2005-08-21 22:31:01 +0000 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2005-08-21 22:31:01 +0000 |
| commit | 5b28c8c3552626eb4beda42731232bc697073264 (patch) | |
| tree | 77b9379e093922a2cb5053e21e7dca3c532cf2de | |
| parent | cc884a3506a428e1d0000b24bbbb1d2fdf3add29 (diff) | |
| download | ffmpeg-5b28c8c3552626eb4beda42731232bc697073264.tar.gz | |
time_base description by Rich Felker | dalias, aerifal cx
Originally committed as revision 4536 to svn://svn.ffmpeg.org/ffmpeg/trunk
| -rw-r--r-- | libavcodec/avcodec.h | 7 | ||||
| -rw-r--r-- | libavformat/avformat.h | 7 | ||||
| -rw-r--r-- | output_example.c | 5 |
3 files changed, 16 insertions, 3 deletions
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h index ab00920bc1..e4900dc335 100644 --- a/libavcodec/avcodec.h +++ b/libavcodec/avcodec.h @@ -732,14 +732,17 @@ typedef struct AVCodecContext { void *extradata; int extradata_size; - /* video only */ /** - * time base in which the timestamps are specified. + * 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. * - encoding: MUST be set by user * - decoding: set by lavc. */ AVRational time_base; + /* video only */ /** * picture width / height. * - encoding: MUST be set by user. diff --git a/libavformat/avformat.h b/libavformat/avformat.h index e891b9768d..8b751520c3 100644 --- a/libavformat/avformat.h +++ b/libavformat/avformat.h @@ -229,6 +229,13 @@ typedef struct AVStream { int codec_info_nb_frames; /* encoding: PTS generation when outputing stream */ AVFrac pts; + + /** + * 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. + */ AVRational time_base; int pts_wrap_bits; /* number of bits in pts (used for wrapping control) */ /* ffmpeg.c private use */ diff --git a/output_example.c b/output_example.c index f61229dedd..6091d85089 100644 --- a/output_example.c +++ b/output_example.c @@ -199,7 +199,10 @@ AVStream *add_video_stream(AVFormatContext *oc, int codec_id) /* resolution must be a multiple of two */ c->width = 352; c->height = 288; - /* frames per second */ + /* 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. */ 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 */ |