0002808: BT601 Color Matrix HD Source (Canon DSLR's) encoded in 1080P HD BT709 Project Matrix is not converted. Pinks to Orange.

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Date Submitted

Last Update

0002808

Kdenlive

Rendering

public

2012-11-01 01:22

Reporter

yellow

Assigned To

Priority

normal

Severity

minor

Reproducibility

always

Status

new

Resolution

open

Platform

64 bit

Ubuntu

OS Version

12.10

Product Version

Recent git

Target Version

Fixed in Version

Summary

0002808: BT601 Color Matrix HD Source (Canon DSLR's) encoded in 1080P HD BT709 Project Matrix is not converted. Pinks to Orange.

Description

Annoyingly a number of DSLR's including Canon T2i's encode h264 with BT709 color primaries but BT601 color matrix. It's flagged in the metadata and utilities like ffplay display correct results.

Kdenlive / MLT recognize and assign it as a BT601 color matrix and therefore previews in both Clip & Project Monitors are correct which is great.

But as the 'standard' for rec709 HD video is BT709 color matrix and kdenlive HD Project Profiles follow that, when encoding out to HD h264 or mpeg2 containing BT601 color matrixed sources there appears to be no conversion of the matrix BT601 -> BT709, as a result blue hues turn towards green and pink hues turn towards orange, the latter having an unwanted effect on skin tone.

Yes it's possible to create a custom BT601 matrixed HD project in kdenlive / MLT which is great and metadata to flag BT601 can be added in a remux, but that's really non 'standard', detrimental, confusing for mixed HD source projects and can lead to misinterpretation, default handling by a media player for HD pixel resolution is BT709.

Also as preview in kdenlive respects the differences and therefore anyone grading in kdenlive will be judging adjustments in the monitor previews, when it comes to playback of the encoded project outside of kdenlive results will almost certainly differ.

I've attached a couple of images to illustrate the problem. A Project Monitor frame grab of correct rendition and a frame extracted via a controlled RGB conversion in Avisynth from the same source clip encoded out from kdenlive using a HD project profile.

I'm aware this again may seem a little pedantic, would it be possible to implement?

Sunabs git build

Issue History
Date Modified	Username	Field	Change
2012-11-01 01:22	yellow	New Issue
2012-11-01 01:22	yellow	File Added: BT601_Matrix_Source.png
2012-11-01 01:22	yellow	File Added: BT601_Matrix_Source_Encoded_BT709_Proj.png

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