在 2015/1/22 12:29, Philip Langdale 写道:
On Thu, 22 Jan 2015 12:15:44 +0800
Agatha Hu <a...@nvidia.com> wrote:
We will fix the issue in driver, overscan compensation will be
applied to input DAR *only* if the DAR is 4:3 or 16:9, otherwise
won't unnecessarily modify the aspect ratio for resolutions like
720x480 and 720x576.
The fix will be on future driver, I'll let you know when the branch
is released.
Please, no. We do not want overscan compensation to be done by nvenc at
all. The compensation makes nvenc inconsistent with *all* other
encoders in ffmpeg. For every other encoder, if my input is 720x576 at
[64/45], then my output is the same. It does not do anyone any favours
for nvenc to implicitly alter the output DAR.
There is a separate discussion about whether DAR 'compensation' is
desirable in an encoder or not, but even if that discussion results in
a decision to apply DAR compensation at encode time, it will be done
globally in ffmpeg for all encoders - ie: at a layer above any
individual codec.
If nvidia feels it is important to offer this compensation 'feature',
then I would ask for a configuration option to turn it off - otherwise
we will need the 'de-compensation' logic in the patch I posted.
Thanks,
--phil
Disabling compensation is the best result, adding a flag is acceptable,
but NVENC5.0 has just released, such option won't be available until 6.0
is available, so...
Still waiting for nvenc teams feedback, the worst case is adding the
'de-compensation' logic for 4:3 and 16:9
Agatha Hu
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