[FFmpeg-devel] [PATCH 2/7] avcodec/ffv1enc: add information message when version is changed by the encoder

[Jerome Martinez]

On 09/03/2018 03:15, Michael Niedermayer wrote:
> On Thu, Mar 08, 2018 at 03:12:26AM +0100, Jerome Martinez wrote:
>>
>> checking range coder part, I see that currently there is actually a slight
>> difference with the other AV_LOG_INFO, I don't indicate the message when
>> level is not indicated, as I didn't see the value added of such information
>> when level is not indicated on the command line when I implemented the test.
>>
>> With patch proposal:
>>
>> ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
>> a.mkv
>> [ffv1 @ 00000232D35B9240] bits_per_raw_sample > 8, forcing range coder
>> (no change)
>>
>> ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
>> -coder 0 a.mkv
>> [ffv1 @ 0000014B9B1771C0] bits_per_raw_sample > 8, forcing range coder
>> (no change)
>>
>> ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
>> -level 0 a.mkv
>> [ffv1 @ 000001BC2B881500] bits_per_raw_sample > 8, forcing version 1
>> [ffv1 @ 000001BC2B881500] bits_per_raw_sample > 8, forcing range coder
>> ("version 1" line added because user specified version 0, IMO encoder should
>> inform user that this is not respected)
>>
>> ffmpeg f lavfi -i mandelbrot=s=1920x1080 -vf format=gbrp9 -vframes 1 -c ffv1
>> -level 0 -coder 0 a.mkv
>> [ffv1 @ 000001EAC7685180] bits_per_raw_sample > 8, forcing version 1
>> [ffv1 @ 000001EAC7685180] bits_per_raw_sample > 8, forcing range coder
>> ("version 1" line added because user specified version 0, IMO encoder should
>> inform user that this is not respected)
> I have the suspicion there are more corner cases that behave odd, but ive
> no time ATM to test, ill do that tomorrow unless i forget

I'll add some tests about respecting or displaying the change compared 
to the command line in FATE.

>
>
>> Just for being clear: do you want info message also when level/version is
>> *not* indicated on the command line?
> some sort of debug level message indicating the version may be usefull
> if theres nothing showing it currently

For debug log, I suggest to provide all impacting config items, i.e. 
version, slice count, coder type...

>
> at higher level i think it should only be shown if its worth it to the
> user like for example if it overrides what was speified or somehow has
> compatibility issues

So my patch is fine, and there is the need to change the current 
behavior for the other log line, I'll do another patch.

But for the moment I prefer to have the already FFV1 related pending 
items (7 FFmpeg patches and 5 FFV1 spec patches) handled for better 
seeing the direction to go before adding new items to the list.