dominiquegreffard Posted June 12, 2013 Report Share Posted June 12, 2013 Hi all, Did some search and couldn t come up with any suitable answer. Video monitoring creates a delay between sound and image that makes judging proper lipsync on music video challenging when looking at monitor. I ve used simple technique to guesstimate delay with a slate listening to my erx ifb but i d like to have a way to have a proper time measurement? Filming fs700 hdmi to hdmi to sony monitor guesstimate gives me around 80ms. Any ideas? Cheers! Quote Link to comment Share on other sites More sharing options...
Ken Wilkinson Posted June 12, 2013 Report Share Posted June 12, 2013 This is what I use to calculate video delay in the studio. Pretty standard in post houses. http://www.pharoahaudio.com/syncheckproducthomepage.html Quote Link to comment Share on other sites More sharing options...
dominiquegreffard Posted June 12, 2013 Author Report Share Posted June 12, 2013 It s nice but it s 500$. I ll stick with the guesstimate untill i find a quick trick for onset applications. But thanks for the heads up! Quote Link to comment Share on other sites More sharing options...
Ken Wilkinson Posted June 12, 2013 Report Share Posted June 12, 2013 It s nice but it s 500$. I ll stick with the guesstimate untill i find a quick trick for onset applications. But thanks for the heads up! It's not cheap but it does it's job very well. I learned the hard way sync might not be what you think it is in post. Different monitors, different codecs and different video cards each have their own delay. I was lucky enough to find mine on ebay for $0.99. Luckily nobody else knew what it was Quote Link to comment Share on other sites More sharing options...
pindrop Posted June 12, 2013 Report Share Posted June 12, 2013 This is what I use to calculate video delay in the studio. Pretty standard in post houses. http://www.pharoahaudio.com/syncheckproducthomepage.html Interesting how does it work please? What does it measure against what? Quote Link to comment Share on other sites More sharing options...
Ken Wilkinson Posted June 12, 2013 Report Share Posted June 12, 2013 You load its calibration videos into you DAW, they have beep and a visual pop that play in sync. You play the files back and point the device at the screen and it measures the offset between the audio and the video delay in either quarter frames or milliseconds. Then you take those numbers and use them to delay the audio to match the video delay. Quote Link to comment Share on other sites More sharing options...
pkautzsch Posted June 13, 2013 Report Share Posted June 13, 2013 ...but you can't do this with a monitor on location, fed a live picture from a camera, can you? Quote Link to comment Share on other sites More sharing options...
Ken Wilkinson Posted June 13, 2013 Report Share Posted June 13, 2013 ...but you can't do this with a monitor on location, fed a live picture from a camera, can you? Guess not. Best solution I could think of Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted June 14, 2013 Report Share Posted June 14, 2013 My advice: guess. Try 2 frames, which is usually pretty close to 80 milliseconds (assuming about 24 video frames per second). If that doesn't work, add another frame. If they're going through a downconverter and watching standard def, all bets are off. It could be anything. Keep dialing it in until it looks right. Quote Link to comment Share on other sites More sharing options...
Jim Feeley Posted June 14, 2013 Report Share Posted June 14, 2013 Marc's advice looks good. Perhaps this chart from a Sound Devices tech note would be handy guide. Perhaps not, but it's helped me when setting up a PIX, so what the heck: http://www.sounddevices.com/notes/pix/sync-offset/ Sync Offset When Using PIX Audio Inputs with Camera Video [i cut the useful info on how to compensate for video delay when recording to a PIX] "Below is a table indicating the input delay setting (milliseconds) required to compensate for different amounts of video delay. The top row (1-10) indicates the amount of video delay in frames and the left column corresponds to the frame rate being used." Quote Link to comment Share on other sites More sharing options...
RadoStefanov Posted June 14, 2013 Report Share Posted June 14, 2013 Get a camera that shoots photos and the video camera. Point the video camera at a sound synced slate and take a picture of the actual slate and the image in the monitor... Quote Link to comment Share on other sites More sharing options...
Jesse Flaitz Posted June 14, 2013 Report Share Posted June 14, 2013 http://quietart.co.nz/catchinsync/ Free app, might be what you are looking for? Quote Link to comment Share on other sites More sharing options...
John Blankenship Posted June 14, 2013 Report Share Posted June 14, 2013 http://quietart.co.nz/catchinsync/ Free app, might be what you are looking for? While this app may very well work fine, I'd have more confidence in the developers if they understood that it's the video that's out of sync, not the audio: "... In almost all cases where audio and video playback passes through separate devices ... there will be advancement or delay on the audio signal, making the viewing experience unpleasant..." Thus further perpetuating the misunderstanding and myth that the problem originates with sound. Quote Link to comment Share on other sites More sharing options...
dominiquegreffard Posted June 14, 2013 Author Report Share Posted June 14, 2013 Get a camera that shoots photos and the video camera. Point the video camera at a sound synced slate and take a picture of the actual slate and the image in the monitor... Smart! Quote Link to comment Share on other sites More sharing options...
dominiquegreffard Posted June 14, 2013 Author Report Share Posted June 14, 2013 http://quietart.co.nz/catchinsync/ Free app, might be what you are looking for? Great tip, i will most definetly try it next day on set. Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted June 15, 2013 Report Share Posted June 15, 2013 Below is a table indicating the input delay setting (milliseconds) required to compensate for different amounts of video delay. The top row (1-10) indicates the amount of video delay in frames and the left column corresponds to the frame rate being used. Note that the 33 millisecond per frame only works for 30fps video. 24fps video would be about 40 milliseconds per frame. But in the real world, nobody's gonna notice 7 milliseconds of difference. Once you get over 1/2 frame, then it becomes an issue... and it can add up at different parts of the signal path, especially in large facilities, live shoots, and other situations like that. I agree with John B above that it's the video that's typically delayed by processors in the signal path, making sound fall ahead. When that happens, we have to introduce a delay for the sound to compensate. So it starts with a video problem, not a sound problem. Quote Link to comment Share on other sites More sharing options...
RadoStefanov Posted June 15, 2013 Report Share Posted June 15, 2013 dominiquegreffard mentioned he has an erx ifb. Erx sets delay by half frames. So no need for tables .. Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted June 19, 2013 Report Share Posted June 19, 2013 BTW, the way we used to check sync accuracy in video post was, we'd dub off the segment to Digital Betacam, which was extremely accurate in regards to picture and sound, plus we could jog in half-frame increments. So if we jogged and saw a picture, then got the sound 1 frame late (or a frame early), it was easy to compute the additional delay necessary and fix it. This is also easy with digital files, though all picture editing systems I'm aware of (like Avid, Premiere, and FCP) only jog in 1-frame increments, with no sub-frames. Any good editor can just watch the slate clap and instantly tell if it's a frame early or a frame late. A hand clap works fine. I used to use "door slam sync" frequently on shows where they forgot to slate. Nothing's worse than when sound is early -- this really irritates people on a subconscious level. Quote Link to comment Share on other sites More sharing options...
Philip Perkins Posted June 20, 2013 Report Share Posted June 20, 2013 Sync is in the eye of the beholder, so adjust the sync until it looks good to whoever is writing the check. philp Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted June 23, 2013 Report Share Posted June 23, 2013 Sync is in the eye of the beholder, so adjust the sync until it looks good to whoever is writing the check. And that is the right answer! If it's just on-set playback, it's not that big a deal. I would be much, much pickier if this were a final delivery master, where it has to be absolutely in sync. Quote Link to comment Share on other sites More sharing options...
mikewest Posted August 6, 2013 Report Share Posted August 6, 2013 Great John We do not create the delay so should not be called on to sort it NMD (not my department) mike Quote Link to comment Share on other sites More sharing options...
dominiquegreffard Posted August 6, 2013 Author Report Share Posted August 6, 2013 Great John We do not create the delay so should not be called on to sort it NMD (not my department) mike I get your point but if we have the ability to delay our sound to match the late picture why not just do it? They cannot get the image there any faster afaik. It s a flip of a switch on a ERX. I don t mind helping the other departments if it gets me home faster or it simply makes a better product if it s within reason. I wouldn t drive the gripping truck but i can bring a sandbag once in a while u know.. The counter productive attitude of some technicians sometimes really bug me. Being open to help others will be returned when you will need a favor from other departments down the line. I feel it s common sense or is it just my small set mentality. Who knows? Quote Link to comment Share on other sites More sharing options...
studiomprd Posted August 6, 2013 Report Share Posted August 6, 2013 " I don t mind helping the other departments... " ...especially if it increases my rental income. Quote Link to comment Share on other sites More sharing options...
mikewest Posted August 6, 2013 Report Share Posted August 6, 2013 I'm not being counter productive and I do help other departments. I spend more time dealing with camera feed issues, timecode jamming and multiple headsets than I spend on dealing with my primary focus of getting good sound. Every video split system is different. Different delays, different connectors, different levels. Delegation is the art of responsibility, sorting out other peoples problems is a distraction and we all need to focus on the job we are there for. mike Quote Link to comment Share on other sites More sharing options...
Philip Perkins Posted August 7, 2013 Report Share Posted August 7, 2013 I don't mind supplying a cheap audio delay in the Comtek line if it helps the show, but as was pointed out one can easily end up in a situation with varying amounts of real or perceived delay due to the listener's proximity to the talent and the various monitors and video signal processing in play. I have done shoots where I had to set up as many as 3 different audio delays for various monitor systems at the same time, but I made sure I was getting paid for it. Otherwise--one delay, if any. Most of the time it seems that people don't even notice the sync issues in on-set monitoring....weird. philp Quote Link to comment Share on other sites More sharing options...
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