[FFmpeg-trac] #730(FFmpeg:new): Generate timestamps for source (like do-timestamp=true in gstreamer)

FFmpeg trac at avcodec.org
Sat Dec 10 06:11:34 CET 2011

#730: Generate timestamps for source (like do-timestamp=true in gstreamer)
             Reporter:  hackeron  |                     Type:  enhancement
               Status:  new       |                 Priority:  normal
            Component:  FFmpeg    |                  Version:  unspecified
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
 Many IP cameras have MJPEG streams that vary in framerate depending
 network conditions, ambient light, just plain slow processors on the
 camera itself, etc. This can be anything from 8fps to 30fps - even if the
 camera is set to a fixed framerate.

 Right now, if you set a framerate in ffmpeg, the duration ffmpeg thinks
 the movie is does not match reality, sometimes by a factor of more than
 3x. While ffmpeg supports variable framerate it requires timestamps which
 in this case do not exist.

 Gstreamer has an option called do-timestamp=true that would be very useful
 in ffmpeg. From their website: "Timestamps are set on the buffers as they
 arrive from the camera. These are used by the mime/multipart demultiplexer
 to emit timestamps on the JPEG-encoded video frame buffers. This allows
 the multiplexer to timestamp the frames in the resulting file."

 This would allow ffmpeg to set the timestamp of "now" on every single
 frame as it comes in and know the correct duration of the recording. This
 means correct duration, a/v sync and just being able to seek to specific
 parts of the recording.

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/730>
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