[FFmpeg-devel] [PATCH] Setup for extracting quantization parameters from encoded streams

[Moritz Barsnick]

On Wed, Jul 17, 2019 at 16:18:11 -0700, Juan De León wrote:
> ---
>  libavfilter/vf_extractqp.c      | 116 ++++++++++++++++++++++++++++++++
>  libavutil/Makefile              |   2 +
>  libavutil/quantization_params.c |  28 ++++++++
>  libavutil/quantization_params.h |  98 +++++++++++++++++++++++++++
>  4 files changed, 244 insertions(+)
>  create mode 100644 libavfilter/vf_extractqp.c
>  create mode 100644 libavutil/quantization_params.c
>  create mode 100644 libavutil/quantization_params.h

Is this just an initial proposal and a proof of concept?

The side data which is supposed to come from the codecs isn't available
yet. I don't see AV_FRAME_DATA_QUANTIZATION_PARAMS defined anywhere. I
see no example of how to let the decoders detect the quantization and
insert that side data.

The "extractqp" filter apparently demonstrates how to detect
availability of this side data, i.e. shows how to call
av_frame_get_side_data(). It doesn't do anything useful at all though,
and it isn't included in the build (or documented).

Moritz