[FFmpeg-user] Tagging ProRes as BT.709 not BT.601

[Thomas Worth]

On Thu, Jan 3, 2013 at 5:06 PM, Bob Maple <bobm-ffmpeg at burner.com> wrote:

> On 12/21/2012 4:19 PM, Bob Maple wrote:
>
>  I'm noticing that ProRes I make from ffmpeg import into Avid Media
>> Composer with blown out levels even though I'm pretty sure the data its
>> self is fine.
>>
>> I'm noticing via MediaInfo however that it thinks the color matrix is
>> BT.601 rather than 709, and am wondering if Avid gets confused by not
>> seeing it tagged as 709 and is doing something screwy.
>>
>
> Any ideas on this one?
>
> I've been trying to browse through the source and haven't exactly found
> how/where it's getting tagged with 601, nevermind being able to change it
> to 709...


The host application uses a 601 or 709 decoding matrix based on the values
in the MOV's "colr" atom (specifically, the nclc atom within it). If one
isn't present, it's possible the application will default to 601 for 4:2:2
sources. I'd start looking there. I'm not sure avformat writes such atoms,
however.