Hi Jerome On Thu, Mar 19, 2026 at 10:08:19AM +0100, Jerome Martinez via ffmpeg-devel wrote: > Le 18/03/2026 à 06:06, Lynne via ffmpeg-devel a écrit : > > [...] > > This would not change the amount of memory we would need to allocate, we > > would simply be buffering the entire slice in memory before inverting it > > in the decoder. While it would be faster than doing it for an entire > > image at a time, the memory requirement makes this suboptimal. > > I second that, currently it is possible to just keep in fast memory 2 lines, > and it is an advantage, especially when we need to process 8K content. > > Also, here we talk about an update of FFV1, not FFV2 or any new format, > keeping the process simple and based on what already exists is IMO more > important that getting the "best" (speed? compression ratio? or less > complexity).
Have you checked that the suggested 45° rotated plane cannot be encoded
with a small line buffer ?
Consider this:
FFV1 uses the following past samples to predict the x sample
P
P P P
P P x
rotate by 45°
P P P
P P
x P
Now lets flip it
P P P
P P
P x
This is the exact same pattern and it only touches lines above and samples
in the same line to the left
-> Thus you can encode the green samples as a single plane
with the exact same FFv1 predictor and context models
Its just that instead of rotating the plane you rotate the context and predictor
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
What is money laundering? Its paying someone and not telling the government.
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