[Libav-user] question about AVFormatContext::bit_rate

Jean-Yves Avenard jyavenard at gmail.com
Fri Mar 7 09:03:00 CET 2014


Trying to understand a misbehaviour of mine in an application I'm involved with.

I have adaptative streaming code which makes some decision according
to the field bit_rate in the AVFormatContext structure.

According to the doc:

"Total stream bitrate in bit/s, 0 if not available."

I get very wierd value from there.

Playing a SD mpeg2-ts stream (with one mpeg2 video stream, and a mp2
stereo audio stream); which I know is about 3.5Mbit/s (it's captured
from a DVB-T adapter).

bit_rate value is 756,000 ; so 756kbit/s

That's incredibly low.

Monitoring the network interface, it streams at an average rate of 3.4Mbit/s

A 1080i mpeg2 stream, with an 5.1 AC3 channel (48KHz) shows up at 848kbit/s

So the question becomes:

what exactly does the value bit_rate represents? can we use it ?


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