[FFmpeg-devel] [PATCH v2] swscale: add unscaled conversion from yuv420p to p010

[Hendrik Leppkes]

On Sun, Sep 4, 2016 at 1:18 PM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> 2016-09-04 13:10 GMT+02:00 Paul B Mahol <onemda at gmail.com>:
>> On 9/4/16, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>>> 2016-09-03 15:25 GMT+02:00 Timo Rothenpieler <timo at rothenpieler.org>:
>>>
>>>> +            output_pixel(tdstY++, (t | (t << 8)) & 0xFFC0);
>>>
>>> Please remove the "& 0xFFC0" here and below.
>>
>> Please explain your reasoning here.
>
> The linked specification clearly explains that the content
> of P016 and P010 is identical and that it is not necessary
> to set the lsb's to 0.

While the specification does say that P010's memory layout was
particularly chosen to be able to simply alias to P016 if needed,
having random garbage in there is not good, so the zeroing of those
bits should remain.

- Hendrik