[FFmpeg-devel] [PATCH 1/4] avcodec/frame: add AV_FRAME_FLAG_LOSSLESS

[Marton Balint]

On Mon, 16 Dec 2024, Anton Khirnov wrote:

> Quoting Marton Balint (2024-12-15 01:02:42)
>> Signed-off-by: Marton Balint <cus at passwd.hu>
>> ---
>>  doc/APIchanges       | 3 +++
>>  libavcodec/version.h | 2 +-
>>  libavutil/frame.h    | 4 ++++
>>  3 files changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/doc/APIchanges b/doc/APIchanges
>> index 3a75b803a9..bfba0946d3 100644
>> --- a/doc/APIchanges
>> +++ b/doc/APIchanges
>> @@ -2,6 +2,9 @@ The last version increases of all libraries were on 2024-03-07
>>
>>  API changes, most recent first:
>>
>> +2024-12-xx - xxxxxxxxxx - lavc 61.27.100 - frame.h
>> +  Add AV_FRAME_FLAG_LOSSLESS.
>
> I feel ambivalent about this. This is really a decoder property, and
> attaching it to frames allows it propagate far away to places where it
> makes no sense (the same holds for other existing AVFrame fields, but
> I'd prefer for them to be removed).

The way this flag is set in patch 2 in the series kind of shows why this 
is a per-frame property, directly originated from the bitstream of codecs 
supporting both lossy and lossless encoding. The encoder for such codecs 
is allowed to decide on a frame-by-frame basis if it will use lossy or 
lossless encoding.

Regards,
Marton