[FFmpeg-devel] modify ffplay for dumpstream in rtsp?

Nicolas George george at nsup.org
Sat Oct 3 10:45:25 CEST 2015

Le duodi 12 vendémiaire, an CCXXIV, Jan Panteltje a écrit :
> I was thinking about adding a command line option to ffplay to enable the
> 'dump to stdout' modification, but am taken aback by why I do not
> understand the double speed effect in playback.

Well, patches are usually welcome here if they add an useful feature.

The double speed effect is probably caused by you saving the packets
payloads but not their headers. The result is an elementary stream, it works
more or less depending on the codec, and frequently lacks some information,
especially timestamps, or at least timestamps recognized by the decoders.
Timestamps problem => speed problem.

If you want to contribute, you have to more or less follow these guidelines:

- Work with the git head version. The 1.1 version you are using is ancient
  and no longer supported, your change would not work on it (there is no
  longer a pkt variable at this point).

- Commit your change and use git to produce a proper patch proposal (git
  send-email or git format-patch).


I do not think this feature is useful, at least as is: it has too many
limitations, and I am pretty sure it can already be done in a different but
more robust way.

Most importantly, if ffplay is capable of playing the stream, then ffmpeg
should be able to read and manipulate it, there are no real doubts about it.
I suggest you go to the users mailing-list and try to get help making it
work. If it works with ffmpeg, then we can see if your proposal still brings
an useful enhancement; if it does not work, then we will endeavour to make
it work.


  Nicolas George
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