[FFmpeg-devel] [PATCH 05/11] avcodec/h264_parser: Reuse the RBSP buffer

[Kieran Kunhya]

On Fri, 16 Aug 2019 at 04:20, Andreas Rheinhardt <
andreas.rheinhardt at gmail.com> wrote:

> Up until now, the H.264 parser has allocated a new buffer for every
> frame in order to store the unescaped RBSP in case the part of the RBSP
> that will be unescaped contains 0x03 escape bytes. This is expensive
> and this commit changes this: The buffer is now kept and reused.
>
> For an AVC file with an average framesize of 15304 B (without in-band
> parameter sets etc.) and 132044 frames (131072 of which ended up in the
> results) this reduced the average time used by the H.264 parser from
> 87708 decicycles (excluding about 1100-1200 skips in each iteration)
> to 16963 decicycles (excluding about 10-15 skips in each iteration).
> The test has been iterated 10 times.
>

If I understand correctly, this patch means if you have a large frame (or
large NAL) you are stuck with the large allocation of memory until the
decoder is closed.
Not sure if you have read the discussion here
https://patchwork.ffmpeg.org/patch/5631/

Kieran