Redcine-X Transcoding to H264 results in occasional picture scrambling

[Jeremy Morrison]

Sorry if this issue has been raised elsewhere. If it has been, I was unable to find it.

My workflow requires a low resolution transcoded quicktime h264 with a timecode burn-in to be sent out to transcribers, writers, etc. The problem I am having is that the picture will occasionally get scrambled (see screen shots below) during the transcoding process. I've tried re-transcoding the files and sometimes this works, sometimes it doesn't. Has anyone else encountered this issue or possibly suggest some ways to correct it?

Machine: Mac Pro, 2.4ghz Quad-Core Intel Zeon. 17gb RAM. ATI Radeon HD 5770. RED Rocket. Kona 3 card.
Software: Redcine-X build 501.

Original R3D footage: Shot with RED ONE at 4kHD, 23.98, REDCODE28

Redcine-X Transcoding settings: Full debayer, 480x270 Quicktime H.264, key frame every 24 frames, frame reordering enabled, single-pass, medium quality, burn-in enabled, audio enabled, software scaling Mitchell.

Any help or suggestions would be much appreciated. Thanks!

 

[Matthew Yaeger]

That really looks like corrupt footage. Does the same frame always have the same error? Does it look like this in the RCX viewer when you scrub to the frames that look like that?

Where are you reading your source media from? internal drive? External drive? CF card?

~Matt

 

[Scott Snare]

Looks like an issue I had while transferring r3d's from a CF card reader to a hard drive. The readers electronics overheated due to the high usage and cause corruption. Had to constantly rotate 4 readers and use ice packs to keep things cool. Something in your workflow may be getting to hot with high usage. Just a guess though.

 

[Jeremy Morrison]

That really looks like corrupt footage. Does the same frame always have the same error? Does it look like this in the RCX viewer when you scrub to the frames that look like that?

Where are you reading your source media from? internal drive? External drive? CF card?

~Matt

Hi Matt. The original footage looks great. No issues at all. And if I transcode to say, 1920x1080 ProRes to cut with, it transcodes fine. And no, it's not on the same frame. It seems to happen randomly. I should also mention these are spanned R3D files. The data is on an external RAID connected via FW800.

 

[Deanan]

Hi Matt. The original footage looks great. No issues at all. And if I transcode to say, 1920x1080 ProRes to cut with, it transcodes fine. And no, it's not on the same frame. It seems to happen randomly. I should also mention these are spanned R3D files. The data is on an external RAID connected via FW800.

It could be the firewire cable being intermittent or too many bus powered devices on the firewire bus.
Somewhere along the line, data from the external drive is getting corrupted.

 

[Ivan Cortazar]

I've had a similar prOblem. He original card was fins but when transferred I'd get these images. I hanged the FireWire cable and then transferred find. Since then I always carry at least two different FireWire cables on set.

My 2 cents.

 

[Jeremy Morrison]

It could be the firewire cable being intermittent or too many bus powered devices on the firewire bus.
Somewhere along the line, data from the external drive is getting corrupted.

I'll try transferring the R3D files to an internal drive and see what happens. If the FireWire bus is being stretched to its limits, is this expected?

 

[David Battistella]

Is that frame like that on the R3D you are transcoding from?

I would also suggest an x264 encoder instead of H264, better, faster, less hassles and easy for a transcriber to install.