[Libav-user] [FFmpeg-user] "Smoothing" RTSP over wlan

Michael Fritscher michael.fritscher at telematik-zentrum.de
Wed Jun 27 09:58:03 EEST 2018

Good morning,

thanks for your answer! My comments are inline.

On 27.06.2018 01:31, Carl Eugen Hoyos wrote:
> 2018-06-25 9:15 GMT+02:00, Michael Fritscher
> <michael.fritscher at telematik-zentrum.de>:
>> Scenario: Using RTSP over wlan to get video from a webcam,
>> using the lib itself.
> Sounds like wrong mailing list:
> http://ffmpeg.org/contact.html#MailingLists
Oh, sorry, somehow missed this. Subscribed & changed :-)
>> the WLAN has the characteristic to "pause" for e.g. 300 ms,
>> and send all the data at once. This makes the stream not
>> exactly smooth. Is there a way to tell the libav to buffer / wait
>> 500 ms and let the lib smooth it itself (bei e.g. using the
>> embedded timestamps)?
> I don't think this would be very useful, fast delivery is typically
> expected.
In my case, 300...500 ms more delay is acceptable if then the stream
doesn't stutter any more. In addition to stutter, sometimes I get
messages of "need to consume buffer now" (which is a sign that packets
are delayed too much) - in such cases I get even picture distortions.
>> Or must I smooth it myself (by buffering the pictures - which
>> needs a lot of memory - 25/2*1280*720*3 = round about = 35 MB).
> You could buffer a few input frames.
Yes, this is one of the options, but I would like to avoid it, because
it needs much memory (the mentioned 35 MB - multiple times as I work
with 3-4 streams at the same time). I hoped that I can instruct the lib
to buffer the compressed packets, which needs much less memory. I could
try to implement a proxy as well, but this sounds like much work...

Best regards,
Michael Fritscher

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