On 05.01.2022 06:39, Andreas Rheinhardt wrote:
> It is the common code (that is compiled depending upon CONFIG_NVENC)
> that uses ff_alloc_a53_sei(), so it is natural to make nvenc itself
> select atsc_a53.
> This fixes compilation errors in case nvenc is enabled
> (e.g. autodected) with both nvenc-based encoders disabled.
> (This works in case of static linking (nothing pulls in nvenc.o),
> but it fails with shared builds.)

The correct way to do this would probably just be to stop building 
nvenc.c when just nvenc is enabled, but instead move it to the two nvenc 
encoders.
It being like it currently is mainly has historical reasons, as it 
started out as single file encoder.

> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
> ---
> It would also be obviously desirable to disable nvenc if it is
> not needed if it is only autodetected and not explicitly enabled.
> Maybe it should even be unconditionally disabled if unused.

I don't think configure has any capability to do that? i.e. disable 
flags that nothing uses?
But if both encoders are disabled, nvenc.c should not be built at all 
anymore if changed as suggested above.