[FFmpeg-user] Problem with pixel format and/or missing constant

Ted Park kumowoon1025 at gmail.com
Thu Mar 12 00:17:01 EET 2020


Hi,

> All features specific to "baseline" (which do not exist in main and
> high) are neither
> supported by any available H.264 encoder nor decoder (including libavcodec).
> All this features were removed for "constrained baseline" which is supported by
> all H.264 encoders and all H.264 decoders (even if they call it "baseline”).

Can you elaborate (i.e. on the features removed)? I had been under the impression that baseline and constrained baseline didn’t specify any encoding feature restrictions and basically a name change for non-technical reasons. I just went back to read this from the ITU spec to read:
> NOTE – This specification of the Constrained Baseline profile is technically identical to specification of the use of the Baseline profile with constraint_set1_flag equal to1. Thus, any existing specifications (in other documents that reference this Recommendation | International Standard) that have referred to the use of the Baseline profile with constraint_set1_flag equal to 1 should thus be interpreted as continuing in force as being technically identical to referring to the use of the Constrained Baseline profile (without any need for revision of these existing specifications to instead refer explicitly to the use of the Constrained Baseline profile). 
> 

And sure enough it doesnt really say what I originally thought, I think when I go through the profile requirements, basically weighted prediction and entropy coding of any kind is not allowed in constrained baseline and no random slice order, as opposed to the original definition for baseline, is that correct?


Regards,
Ted Park



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