[FFmpeg-user] ProRes XQ 12-bit support

[Paul B Mahol]

On 4/20/18, Elliott Balsley <elliottbalsley at gmail.com> wrote:
>>
>> Or more likely a marketing issue.
>
> I think maybe what is happening is that since Resolve processes images in a
> 32-bit space, and it's not convenient to fit 12-bit words, it pads each word
> to 16-bits so then it fits better.
>
> Anyway, on this topic, is there a way to definitely read the bit depth used
> to encode a file?  According to Arri, the ProRes 444 clips created by the
> Alexa camera are written using 12 bits.  This is documented in many places
> on the web, including this forum post.  But somehow, ffmpeg identifies these
> files as yuv444p10le and the image looks correct.
> https://www.arri.com/forum/viewtopic.php?t=127&p=266
> <https://www.arri.com/forum/viewtopic.php?t=127&p=266>
>
> If the image were truly 12-bit, and ffmpeg decodes it as 10-bit, I expect
> the image would look wrong.
>
> According to the MediaInfo developer, there is no way to definitely read the
> encoded bit depth, and therefore he has removed that info from the MediaInfo
> tool.
> https://sourceforge.net/p/mediainfo/discussion/297610/thread/4bc21b18/#cd3a/2395/563e/1fec
> <https://sourceforge.net/p/mediainfo/discussion/297610/thread/4bc21b18/#cd3a/2395/563e/1fec>
> <https://sourceforge.net/p/mediainfo/discussion/297610/thread/4bc21b18/#cd3a/2395/563e/1fec>
> <https://sourceforge.net/p/mediainfo/discussion/297610/thread/4bc21b18/#cd3a/2395/563e/1fec>
> <https://sourceforge.net/p/mediainfo/discussion/297610/thread/4bc21b18/#cd3a/2395/563e/1fec>

Two or more wrongs do not make one good.