[FFmpeg-user] Transrating of G.711 RTP from 20ms to 30ms

Julien Nephtali jnephtali at gmail.com
Fri Dec 7 20:53:17 CET 2012

I am trying to transrate an incoming stream of RTP G.711 packets that have
a size of 20ms to an outgoing stream of G.711 packets of 30ms.

I set up a steam of G.711 RTP traffic at 20 ms (packet size= 160)

*ffmpeg -i ./tornado_spotted.wav -re -vn -acodec pcm_alaw -f rtp rtp://*
This test stream is sent to a second ffmpeg that I want to use to transrate
the RTP stream to a packet size of 30ms. Here is the command.

*# ffmpeg -i ./test_stream.sdp -vn -acodec pcm_alaw -f rtp

However the *pkt_size* setting seems to be a maximum packet size setting
and does not force the transrating of the packet. Does anyone know how I
could force the transrating ?


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