Camera flashes causing issues at DVinfo.net

Rob Harlan · March 10th, 2010, 10:33 AM

I don't have many problems with Photographers (so far!), we seem to have a mutual understanding and I accept and even utilise the presence of him/her on the wedding day in my videos.

Recently, I have noticed an issue with their flashes however. When I burn a DVD, some of the 'biggest'/closest flashes are resulting in a brief frame of macro-blocking in my video picture - i.e. in the moment the flash goes off, the sudden near 'white-out' is not merely a bright burst, but a bright burst of unsightly white blocks surrounding the subject. This is not good, as (at least to those knowledgeable) it looks like bad compression.

The blocking is not present in the original footage (Canon, Standard Definition), nor is it present in any .avi file I make from my editor. So the issue is ocurring during conversion to DVD format.

I use Avid Liquid, and convert within that program at a bitrate of around 8000. I haven't had the time to peform extensive tests yet to see if I can stop this blocking happening, but in the meantime any fellow Videographers with similar issues past or present may be able to shed some light. It may be editor or bitrate related, I'm not sure. I could try a different MPEG converter in due course if necessary.

Philip Howells · March 10th, 2010, 06:29 PM

I'm not sure I can give you the complete answer you're seeking because my set up isn't exactly the same as yours.

Flashes recorded by my cameras (z1) in HDV appear pixelated during the edit on Liquid. However, after encoding for DVD (SD) using TMPGEnc and played back as a DVD they revert to flashes on-screen ie the pixelation is a computer-only phenomenon.

As I say there's not enough here to give you a definitive answer but I think I'd first try encoding using TMPGEnc. I think you can download a test version.

Christopher Figueroa · March 10th, 2010, 11:53 PM

When you are playing back the DVD, what equipment are you using? Have you tried different viewing setups, such as the computer, tv & dvd player, additional tv & ps3?

Are you clients noticing the white bursts as well?

Rob Harlan · March 11th, 2010, 08:12 AM

'Flashes recorded by my cameras (z1) in HDV appear pixelated during the edit on Liquid. However, after encoding for DVD (SD) using TMPGEnc and played back as a DVD they revert to flashes on-screen ie the pixelation is a computer-only phenomenon'

Interesting that you seem to have the 'problem' in reverse. Perhaps when I film in HDV I may see similar pixelation within Liquid...

Christopher:-

The blocking is present in the converted VOB sets on computer and naturally the same when burned to DVD wherever the disc is is played (computer or players) - the blocks are being 'made' during the conversion process, I suspect because of bitrate (8000 CBR - I'll experiment when I can with lower value and/or VBR, though I do not want to compromise overall quality to fix this issue) or my editor underperforming in the DVD conversion. DVD quality is normally very good overall, but if it is Liquid causing the issue regardless of bitrate I will switch to an external encoder.

No client has mentioned the block-bursts, but they are unsightly and definitely something that needs to be/can be fixed.

Roger Van Duyn · March 11th, 2010, 06:19 PM

Rob,

It looks like you use the same settings as me in Liquid when encoding DVDs, 8000 CBR. I haven't experienced the same problem as you, but in Liquid when I've had weird motion artifact kinds of things, fiddling with the bit rate would get rid of them. One day I shot a clip of a cheetah at the zoo walking in front of a light colored rock with bright sunlight reflecting off the rock. There were pixel/blocky looking things around the rock and the cheetah's spots seemed to shimmer or dance. Fiddling with the bit rate cleaned it up. I had actually started with a lower bit rate and raised it to 8000 fixed it.

In your case, I don't know what to say, except raising the bit rate above 8000 will probably interfere with some players playing the disk. I never fooled much with the VBR settings. Maybe try that, if it doesn't work, try TMPGEnc. I haven't used it for years, but there used to be a free trial version.

Hope you can solve the problem. Wish I could help more.

March 10th, 2010, 10:33 AM	#1
Rob Harlan Regular Crew Join Date: Jan 2010 Location: UK Posts: 62	Camera flashes causing issues I don't have many problems with Photographers (so far!), we seem to have a mutual understanding and I accept and even utilise the presence of him/her on the wedding day in my videos. Recently, I have noticed an issue with their flashes however. When I burn a DVD, some of the 'biggest'/closest flashes are resulting in a brief frame of macro-blocking in my video picture - i.e. in the moment the flash goes off, the sudden near 'white-out' is not merely a bright burst, but a bright burst of unsightly white blocks surrounding the subject. This is not good, as (at least to those knowledgeable) it looks like bad compression. The blocking is not present in the original footage (Canon, Standard Definition), nor is it present in any .avi file I make from my editor. So the issue is ocurring during conversion to DVD format. I use Avid Liquid, and convert within that program at a bitrate of around 8000. I haven't had the time to peform extensive tests yet to see if I can stop this blocking happening, but in the meantime any fellow Videographers with similar issues past or present may be able to shed some light. It may be editor or bitrate related, I'm not sure. I could try a different MPEG converter in due course if necessary.

March 10th, 2010, 11:53 PM	#3
Christopher Figueroa Regular Crew Join Date: Mar 2010 Location: New York, NY Posts: 72	When you are playing back the DVD, what equipment are you using? Have you tried different viewing setups, such as the computer, tv & dvd player, additional tv & ps3? Are you clients noticing the white bursts as well? __________________ Chris Fig Productions Wedding Videographer

March 11th, 2010, 06:19 PM	#5
Roger Van Duyn Major Player Join Date: Feb 2009 Location: Lakeland Florida Posts: 692	Rob, It looks like you use the same settings as me in Liquid when encoding DVDs, 8000 CBR. I haven't experienced the same problem as you, but in Liquid when I've had weird motion artifact kinds of things, fiddling with the bit rate would get rid of them. One day I shot a clip of a cheetah at the zoo walking in front of a light colored rock with bright sunlight reflecting off the rock. There were pixel/blocky looking things around the rock and the cheetah's spots seemed to shimmer or dance. Fiddling with the bit rate cleaned it up. I had actually started with a lower bit rate and raised it to 8000 fixed it. In your case, I don't know what to say, except raising the bit rate above 8000 will probably interfere with some players playing the disk. I never fooled much with the VBR settings. Maybe try that, if it doesn't work, try TMPGEnc. I haven't used it for years, but there used to be a free trial version. Hope you can solve the problem. Wish I could help more. __________________ Roger My YouTube Channel: https://www.youtube.com/channel/UCAp...2AHr_pHFID5LDA

March 10th, 2010, 06:29 PM	#2
Philip Howells Trustee Join Date: Jan 2009 Location: Manchester UK Posts: 1,212	I'm not sure I can give you the complete answer you're seeking because my set up isn't exactly the same as yours. Flashes recorded by my cameras (z1) in HDV appear pixelated during the edit on Liquid. However, after encoding for DVD (SD) using TMPGEnc and played back as a DVD they revert to flashes on-screen ie the pixelation is a computer-only phenomenon. As I say there's not enough here to give you a definitive answer but I think I'd first try encoding using TMPGEnc. I think you can download a test version.

March 11th, 2010, 08:12 AM	#4
Rob Harlan Regular Crew Join Date: Jan 2010 Location: UK Posts: 62	'Flashes recorded by my cameras (z1) in HDV appear pixelated during the edit on Liquid. However, after encoding for DVD (SD) using TMPGEnc and played back as a DVD they revert to flashes on-screen ie the pixelation is a computer-only phenomenon' Interesting that you seem to have the 'problem' in reverse. Perhaps when I film in HDV I may see similar pixelation within Liquid... Christopher:- The blocking is present in the converted VOB sets on computer and naturally the same when burned to DVD wherever the disc is is played (computer or players) - the blocks are being 'made' during the conversion process, I suspect because of bitrate (8000 CBR - I'll experiment when I can with lower value and/or VBR, though I do not want to compromise overall quality to fix this issue) or my editor underperforming in the DVD conversion. DVD quality is normally very good overall, but if it is Liquid causing the issue regardless of bitrate I will switch to an external encoder. No client has mentioned the block-bursts, but they are unsightly and definitely something that needs to be/can be fixed.