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QuickTime gamma drop when transcoding from DNxHD to H.264
Has anyone seen a decrease in gamma when transcoding DNxHD/MOV files to H.264 using QuickTime Pro? Images are noticeably darker: grey point in the encoded video is approximately 0.88 of the intermediate files.
Here are the specifics:
– DNxHD-90-720-24-10bit/MOV with RGB and 709 color, exported at 48-bit depth setting from Premiere Pro CS6 v6.0.3
– DNxHD file opened in QuickTime Pro v7.6.9 on Win7-64
– transcoded to H.264/MP4 at Baseline Profile, 1-Pass and 2-Pass, bitrates from 2500-32768 kbps, key frame distances from 1-24 frames
– also transcoded to H.264/MOV at auto settings, multi-pass
– analyzed using RGB Parade and YC Waveform in Premiere Pro -
2 Replies
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What program are you using to transcode? Apple’s Compressor was known to mess with gamma when going to H.264, usually washing the image out a little bit.
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Thank you for the reply. The files are being transcoded with QuickTime Pro v7.6.9.
One of the characteristics of the QT/Compressor wash-out issue is an increase in brightness within the shadow regions. In this case the video gets darker after transcoding.
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