Choppy image - temporary

Luc De Wandel · January 20th, 2010, 01:42 PM

I experienced something very awkward when burning edited movies from my XDCAM-HD (PDW-F350) to Bluray disk: whenever there's a panning or other motion, the first few seconds the image stutters, but after that everything moves smoothly. So there a a few seconds of choppy video, followed by perfect footage.

How is this possible? Is it a Bluray encoding artefact? (Shot in HD, 25p, edited in FCP, exported to QT in ProRes 422 and encoded that QT-movie to Bluray).

Jon Geddes · January 23rd, 2010, 10:34 AM

Do you know what bitrate it was encoded at? Its possible that during the pans, the bitrate spikes up, causing too high of a data rate for the player to sustain... and skipping. Keep the bitrate under 25 Mbps Max.

Luc De Wandel · January 23rd, 2010, 04:52 PM

Thanks for reacting, Jon.
The bitrate the clips were recorded in originally, was variable (VBR), with a maximum of 30. (XDCAM HD, HQ). The edited sequence was then exported to Quicktime in Apple ProRes422, also with VBR-setting.
But I don't know what bitrate is used during the transcoding to bluray...
It's probably during that last stage that the problem was created, as you suggest by too high a rate for the player to cope with. Is there any way to influence the bitrate (in Toast 10) during the transcoding to Bluray? Without losing quality, that is.

Perhaps, in any case, I could try playing the disk in another player, to see if the problem persists. I've heard that Sony's Playstation is notorious for playing anything you throw at it... Would that be worth a test?

Jon Geddes · January 23rd, 2010, 07:42 PM

Sorry, I am not familiar with Toast so I can't help you with specific settings for that. See if you can do VBR with a max bitrate of 25.

January 20th, 2010, 01:42 PM	#1
Luc De Wandel Major Player Join Date: May 2008 Location: Knokke-Heist, Belgium Posts: 963	Choppy image - temporary - on bluray I experienced something very awkward when burning edited movies from my XDCAM-HD (PDW-F350) to Bluray disk: whenever there's a panning or other motion, the first few seconds the image stutters, but after that everything moves smoothly. So there a a few seconds of choppy video, followed by perfect footage. How is this possible? Is it a Bluray encoding artefact? (Shot in HD, 25p, edited in FCP, exported to QT in ProRes 422 and encoded that QT-movie to Bluray).

January 23rd, 2010, 10:34 AM	#2
Jon Geddes Regular Crew Join Date: Mar 2009 Location: Seal Beach, California Posts: 68	Do you know what bitrate it was encoded at? Its possible that during the pans, the bitrate spikes up, causing too high of a data rate for the player to sustain... and skipping. Keep the bitrate under 25 Mbps Max.

January 23rd, 2010, 04:52 PM	#3
Luc De Wandel Major Player Join Date: May 2008 Location: Knokke-Heist, Belgium Posts: 963	Thanks for reacting, Jon. The bitrate the clips were recorded in originally, was variable (VBR), with a maximum of 30. (XDCAM HD, HQ). The edited sequence was then exported to Quicktime in Apple ProRes422, also with VBR-setting. But I don't know what bitrate is used during the transcoding to bluray... It's probably during that last stage that the problem was created, as you suggest by too high a rate for the player to cope with. Is there any way to influence the bitrate (in Toast 10) during the transcoding to Bluray? Without losing quality, that is. Perhaps, in any case, I could try playing the disk in another player, to see if the problem persists. I've heard that Sony's Playstation is notorious for playing anything you throw at it... Would that be worth a test?

January 23rd, 2010, 07:42 PM	#4
Jon Geddes Regular Crew Join Date: Mar 2009 Location: Seal Beach, California Posts: 68	Sorry, I am not familiar with Toast so I can't help you with specific settings for that. See if you can do VBR with a max bitrate of 25.