[FFmpeg-user] YUV->RGB conversion. What is the default matrix used?

Tim Nicholson nichot20 at yahoo.com
Fri Jul 6 08:35:48 CEST 2012

On 05/07/12 14:03, Mike Scheutzow wrote:
> Tim Nicholson wrote:
>> If I could relate the coefficients as defined in the two files above I
>> might be able to add 634/smpte 170m (they use the same values) to
>> colormatrix to provide a workaround...
> Did you look at the ff_yuv2rgb_coeffs[] table?
> The comments imply that it already defines 170m. But the sws api doesn't

Yes, but the coefficients are the same as 624-4. So is that really the
case, or are they just there for "future expansion" and yet to be
properly populated?

If I understood they way the coefficients are expressed there it would
be easier to confirm what is going on...

> seem to give you an easy way to select it.

But not used afaik...

> You could change SWS_CS_DEFAULT and recompile, if you're willing to
> maintain a private build.

Well I already do anyway so that's not a big issue, but I'm sure I'm not
the only one who would like it to be more selectable, and clear.

> Mike Scheutzow
> [..]


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