[Libav-user] Qp values as side data

pi arctan pi.arctan at gmail.com
Mon Nov 26 23:14:25 EET 2018


Hi everyone.

I'm stuck trying to extract the qp values for a frame using side data in
H.264.
My program vq2.c can be found in https://pastebin.com/cMeg1rpp.
Makefile here: https://pastebin.com/29TfM8gA
and my patch for libavcodec/h264dec.c here https://pastebin.com/tegY3SJj.

Using the code above I get 0 in the qp data. Don't understand why.
Also, av_frame_set_qp_table is deprecated. Is there another way to do this
properly?

I'm making a simple video analysis tool where I need to extract the
following data for each frame:

frame type, frame size, qp min, qp max, qp avg.

As a bonus question I'm trying to get the same data for HEVC but code isn't
really prepared for that.
Anyone knows best place to extract the qp-values for a frame? My current
approach is to do it in the CABAC step but it's not working as expected
(yet). Any hints are appreciated here.

cheers
./Fredrik
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