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Motion JPEG color shift
Hi,
I have noticed that there is visible color shift in file encoded to BM Motion JPEG codec comparing to BM 4:2:2 or 4:4:4. Video is noticable greener and darker. Is there a bug or it is compression artifact? Does anybody catch it? Test videos are rendered from After Effects 7.0 running under Windows XP, 6.0 BM drivers.
Can you help me with it? Otherwise MJPEG should be a killer feature for doing disks-saving relatively HQ previews.
Thanks for any advice…
Jaromir Pesr
i/o post
Prague -
4 Replies
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Hi Jaromir,
I haven’t heard of this problem before. If you have access to a deck, would you please capture color bars from the deck to an uncompressed timeline and then to an MJPEG timeline. Then export a frame from both test clips and email it to support@ blackmagic-design.com so we can see the difference that you have observed?
If the problem only occurs when rendering from After Effects, please provide all necessary steps to replicate the problem so we can check it out for you.
Regards,
Luke Maslen
Blackmagic Design -
Hello Luke,
As you said, last week I have sent a request to bm suport with no single line back untill now. I have to say it is not for a first time there. What can I do to solve this issue, please? This forum seems to be the only place where I can occasionaly contact you, guys. It makes me sad because I love your products…
Regards
Jaromir Pesr
i/o post
Prague -
Hi Jaromir,
I’m sorry you hadn’t received a reply. I checked and the engineers have definitely received your email with the sample files. Thank you for providing those as they clearly demonstrate the problem you have seen. The engineers are working on some driver updates including bug fixes so I’m hopeful that they’ll be able to address your problem in one of the next updates.
Regards,
Luke Maslen
Blackmagic Design -
Hi Jaromir,
You mentioned you were using the DeckLink 6.0 drivers and we believe there was a bug in relation to Motion JPEG in that version which could account for your problem. We believe that upgrading to the current DeckLink drivers will overcome that problem.
We’ve tested this problem with the DeckLink 6.1, 6.1.1 and 6.1.2 drivers and cannot replicate it. We captured PAL colour bars from a D5 deck in the MJPEG, 10-Bit & 8-Bit uncompressed formats and then compared the playback to a waveform monitor. The waveform doesn’t move at all when changing from clip to clip.
Therefore updating to the DeckLink 6.1 or newer drivers should resolve your problem. Please try this and let us know how it goes.
Regards,
Luke Maslen
Blackmagic Design
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