Hi Carl
I would like to use the audio delay feature to get video and audio in sync for a conversion.
Is there any way of playing the file in DCP-o-matic with audio so the delay can be adjusted correctly.
Regards
Peter.
Audio Delay
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carl
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Re: Audio Delay
Hi Peter,
I'm afraid there currently is not. Can you play the file in something else to check it? VLC, perhaps?
I'm afraid there currently is not. Can you play the file in something else to check it? VLC, perhaps?
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Carsten
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- Location: Germany
Re: Audio Delay
Hi Peter,
do you KNOW that the audio is out of sync in the source? What source is it?
You will a have hard time finding a player that is able to show you precise sync between video and audio. You can never be sure that a specific software player is able to play back audio and video in sync on a given non-pro hardware (and most software players do not support pro hardware).
Of course, if you think the sync is off by 2s or something, you can at least get it within reasonable boundaries.
In general, playing around with the delay in dcp-o-matic will make it worse, not better when you try to adjust small sync differences. You will find then that the sync is off then when playing through the DCI machine. If your source has a clear a/v sync marker, e.g. a handclap, you could try to measure that in an AV editor and transfer that value into DCP-o-matic for conversion.
http://www.doremilabs.com/support/cinem ... ineplayer/ (demo, but has VU meters and could be useful for sync checking even with the runtime limitation)
http://www.neodcp.com/ (free demo, runtime limitation)
http://www.digitall.net.au/dcpplayerfree/ (free player with watermark, no runtime limitation. A bit unstable, but free, same software as the Morgan DCP player)
Stereoscopic player will play the raw source MXF files. Bear in mind that the CPL may actually include the sync offset for a feature, so, you could find the raw MXFs out of sync, but not the CPL-referenced playout. But sometimes this is handy to compare both playback variants in order to find sync issues.
VLC will play the audio MXF of a DCP nicely, but will skip heavily on the video part, depending on your machine. Also, neither stereoscopic player nor VLC currently perform the inverse xyz->RGB comversion, so the image will have a greenish tint. The stereoscopic website claims their J2k codec can co inverse xyz - but I haven't found out how to configure that and the author never answered my email.
Heck, download and install them all and give them a try.
Most people suggest the EasyDCP Player demo - the full version is full of features, but I have never found the demo too useful. Also it needs a fast dedicated graphics card for playback, while above solutions work even on older notebooks with onboard graphics nicely for content checks.
- Carsten
do you KNOW that the audio is out of sync in the source? What source is it?
You will a have hard time finding a player that is able to show you precise sync between video and audio. You can never be sure that a specific software player is able to play back audio and video in sync on a given non-pro hardware (and most software players do not support pro hardware).
Of course, if you think the sync is off by 2s or something, you can at least get it within reasonable boundaries.
In general, playing around with the delay in dcp-o-matic will make it worse, not better when you try to adjust small sync differences. You will find then that the sync is off then when playing through the DCI machine. If your source has a clear a/v sync marker, e.g. a handclap, you could try to measure that in an AV editor and transfer that value into DCP-o-matic for conversion.
http://www.doremilabs.com/support/cinem ... ineplayer/ (demo, but has VU meters and could be useful for sync checking even with the runtime limitation)
http://www.neodcp.com/ (free demo, runtime limitation)
http://www.digitall.net.au/dcpplayerfree/ (free player with watermark, no runtime limitation. A bit unstable, but free, same software as the Morgan DCP player)
Stereoscopic player will play the raw source MXF files. Bear in mind that the CPL may actually include the sync offset for a feature, so, you could find the raw MXFs out of sync, but not the CPL-referenced playout. But sometimes this is handy to compare both playback variants in order to find sync issues.
VLC will play the audio MXF of a DCP nicely, but will skip heavily on the video part, depending on your machine. Also, neither stereoscopic player nor VLC currently perform the inverse xyz->RGB comversion, so the image will have a greenish tint. The stereoscopic website claims their J2k codec can co inverse xyz - but I haven't found out how to configure that and the author never answered my email.
Heck, download and install them all and give them a try.
Most people suggest the EasyDCP Player demo - the full version is full of features, but I have never found the demo too useful. Also it needs a fast dedicated graphics card for playback, while above solutions work even on older notebooks with onboard graphics nicely for content checks.
- Carsten
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sguttag
- Posts: 5
- Joined: Thu Dec 26, 2013 9:51 pm
Re: Audio Delay
I had been advised that when converting BluRays that the lipsync will likely be off by about 105msec. As such, I set the delay to 105. Upon a test viewing in a real theatre using equipment where the lip sync has been checked with suitable test material that a DCP O Matic content seemed notably out of sync.
I remoted into the theatre and changed the lip sync on the IMB by -210msec (cancelling out the the original 105 and taking away another 105)...they immediately said that looked much better.
Are there any rules-of-thumb pages for what one would consider "typical" uses of DCP-O-MATIC? I would presume that conversion of Blu-Rays, DVDs, still images and home-grown videos or slide shows would be things most cinemas would want to use it for. Why should everyone have to "discover" on their own the typical settings? Heck, there could even be "hot buttons" that would configure DCP-O-MATIC to make the settings that seem to work best with most content of a particular type. Just a thought.
I remoted into the theatre and changed the lip sync on the IMB by -210msec (cancelling out the the original 105 and taking away another 105)...they immediately said that looked much better.
Are there any rules-of-thumb pages for what one would consider "typical" uses of DCP-O-MATIC? I would presume that conversion of Blu-Rays, DVDs, still images and home-grown videos or slide shows would be things most cinemas would want to use it for. Why should everyone have to "discover" on their own the typical settings? Heck, there could even be "hot buttons" that would configure DCP-O-MATIC to make the settings that seem to work best with most content of a particular type. Just a thought.
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carl
- Site Admin
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Re: Audio Delay
If the source file is in sync and the DCP that DCP-o-matic makes is not, that is a bug in DCP-o-matic, as far as I'm concerned. Brad's strange 105ms delay on Blu-Ray is an open bug that I haven't got to the bottom of yet... but I would hope to fix DCP-o-matic so that it always gets the sync right.Are there any rules-of-thumb pages for what one would consider "typical" uses of DCP-O-MATIC? I would presume that conversion of Blu-Rays, DVDs, still images and home-grown videos or slide shows would be things most cinemas would want to use it for. Why should everyone have to "discover" on their own the typical settings? Heck, there could even be "hot buttons" that would configure DCP-O-MATIC to make the settings that seem to work best with most content of a particular type. Just a thought.
If you have any example video files that exhibit the problem, and they are small enough to transfer to me over the internet, I would be very happy to get hold of them as I can then investigate.
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sguttag
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Re: Audio Delay
I'm so new to this I don't have any examples and have so little time to get this BluRay transferred, I've been standing on other people's shoulders to get a jump on it. And I see you've surmised where I got the 105msec information from!
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Carsten
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- Location: Germany
Re: Audio Delay
The question is, would that sync offset of BluRays be disc dependent, or is it a general bug. I could easily make a DCP from a ripped Home-Theater Setup DVD/BluRay with sync test footage.
But - I have never experienced any sync problems with ripped BluRays and DVDs, not with discs I converted myself, not with discs converted by others.
Or at least, if there are sync offsets, they have been so small that no one, including me, noticed them
As long as that issue is not cleared, I would advise to NOT change the sync offset just as a precaution. Create with 0 delay, and then check it on a cinema system.
- Carsten
But - I have never experienced any sync problems with ripped BluRays and DVDs, not with discs I converted myself, not with discs converted by others.
Or at least, if there are sync offsets, they have been so small that no one, including me, noticed them
As long as that issue is not cleared, I would advise to NOT change the sync offset just as a precaution. Create with 0 delay, and then check it on a cinema system.
- Carsten
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mitochondriax
- Posts: 2
- Joined: Fri Aug 24, 2018 10:51 pm
Re: Audio Delay
I've been having audio delay issues creating DCPs. My setup is as follows: Premiere Pro cc 2018 23.976 multichannel sequence with prores 422HQ with 5.1 audio file consisting of properly assigned mono tracks. Audio sync is spot on both visually and looking at waveforms in PP CC. Export as .mov. Checked in quicktime in which the sync remains accurate. Import into DCP-O-Matic and create DCP. Tested on Dolby systems in two theaters. I've tried four times and the audio is always delayed by between 3 and 5 frames. I've tried moving the audio in Premiere and re-exporting and still have the same issue. Any suggestions? Thanks, Vince
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Carsten
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- Joined: Tue Apr 15, 2014 9:11 pm
- Location: Germany
Re: Audio Delay
It is not uncommon for DCI systems to have their sync misaligned. Very often, people do not notice it.
3-5 frames is a considerable sync offset, though. Which version of DCP-o-matic have you used to create these DCPs? Can you convince these operators to play a mainstream trailer for you to check?
The trouble is, I think there is no 'official' sync check DCP that could convince the cinema operators to check or adjust the settings.
Is there any frame rate conversion involved in this project, like from 25 to 24 or so? Which datarate do you use for the J2K compression in DCP-o-matic?
Maybe you could create a short test with some good sync indicators and upload them somewhere? 5s is enough for me to check it on our system.
- Carsten
3-5 frames is a considerable sync offset, though. Which version of DCP-o-matic have you used to create these DCPs? Can you convince these operators to play a mainstream trailer for you to check?
The trouble is, I think there is no 'official' sync check DCP that could convince the cinema operators to check or adjust the settings.
Is there any frame rate conversion involved in this project, like from 25 to 24 or so? Which datarate do you use for the J2K compression in DCP-o-matic?
Maybe you could create a short test with some good sync indicators and upload them somewhere? 5s is enough for me to check it on our system.
- Carsten
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mitochondriax
- Posts: 2
- Joined: Fri Aug 24, 2018 10:51 pm
Re: Audio Delay
Thanks for the reply Carsten. There is a frame rate conversion from 23.976 to 24. The data rate is 125Mb/s and the version is either the latest or close to the latest. I've watched trailers and they appear to be in sync. I'll try to make an indicative DCP when I get back midweek.
thanks,
Vince
thanks,
Vince