MEP 16: video and audio out of sync

kj-radetski wrote on 7/22/2017, 9:28 PM

So recently I've been recording several different games just to get some footage, about an hours worth. I put it into MEP and the and the video looks and sounds fine, but after about 10 minutes the audio goes out of sync with the video by a few seconds. I record with OBS at constant framerate and I export the video from OBS as a .mp4 file. I'm really confused by this because this has never happened before. I've recorded with OBS many times and edited down the clips with MEP, and I find it really strange that it now does this all of a sudden. I have a suspicion why, which would be that MEP can only accept Variable Framerate videos. But I doubt that's the case.

Comments

johnebaker wrote on 7/23/2017, 4:37 AM

. . . . I record with OBS at constant framerate . . . .

Was the audio bitrate set to constant eg 128 kbps and the sample rate to 48 kHz?

If in doubt, use MediaInfo to analyse the recorded clip which is giving the problem and compare it to others which do work correctly in MEP.

. . . . I have a suspicion why, which would be that MEP can only accept Variable Framerate videos . . .

It will however you can get issues such as the one you are having with audio. Fixed video frame rate and audio bitrate are best.

Do you mean MEP 16 or MEP 2016?

When quoting the program please use the full year name if there is one and version number as found under Help, About .

This will avoid confusion over with earlier versions of the program.

HTH

John EB

DanTheMan wrote on 7/23/2017, 5:49 AM

I observe a similar sync issue (video lagging behind) which I described here:

https://www.magix.info/de/forum/imported-mp4-twitch-video-asynchronous-early-audio-late-video--1193493/

Any ideas how to analyze the video further to get more details about the problem (or better: to fix the problem)?

kj-radetski wrote on 7/23/2017, 1:23 PM

I'm sorry I didn't make it more clear. I use MEP 2016, my sample rate is 44.1khz, I made it this so that it was the same as my mic, and I had the audio bitrate set to 320. Another question I have would simply be, is there a way to fix this in MEP, or would I have to use other outside programs like handbrake to export it differently?

Kami_1 wrote on 7/23/2017, 1:43 PM

"Was the audio bitrate set to constant eg 128 kbps and the sample rate to 48 kHz?"

John, are these the settings for SD or HD?
Kami

johnebaker wrote on 7/23/2017, 3:25 PM

@Kami_1

The audio sample rate for DVD standard video (SD) is 48 kHz and 48, 96 or 192 kHz for Blu-Ray.

The quality of the audio is determined by the bitrate, which is a result of a combination the sample rate, bit depth (16, 20 or higher bits), the no of channels, eg stereo, surround sound etc.

A bitrate of 128 kbps is considered as the minimum for acceptable stereo audio, this is also often referred to as CD quality however this is incorrect - CD quality audio has a higher bitrate 172 kbps or higher with a lower sample rate of 44.1 kHz.

@kj-radetski

. . . . is there a way to fix this in MEP, or would I have to use other outside programs like handbrake to export it differently . . . .

No - the problem is not the bitrates, MEP will work with 44.1 or 48 kHz audio, the issue is that most gaming capture software captures using variable framerate video which can cause out of sync audio.

The problem is finding a third party converter which can convert existing video to constant frame rate and successfully resync the audio to the video.

A solution for future captures is to ensure the capture frame rate is constant - some capture programs will allow this, others have a setting for it to be constant, however they often aim to capture at this rate but drop the frame rate if they start struggling.

If you look through many of the gaming forums you find lots of discussions on this very topic - variable frame rates captures of game play have a big problem with audio sync for many video editing programs that are in common use.

HTH

John EB

Kami_1 wrote on 7/23/2017, 4:37 PM

The audio sample rate for DVD standard video (SD) is 48 kHz and 48, 96 or 192 kHz for Blu-Ray.

The quality of the audio is determined by the bitrate, which is a result of a combination the sample rate, bit depth (16, 20 or higher bits), the no of channels, eg stereo, surround sound etc.

John EB

Hi, This is so confusing!! LOL! Are the Blu-Ray settings the same as those of plain HD? I'm asking because I don't want to cause the audio problems I had with the previous MEP version, by having a wrong bit or sample rate. MEP tells me when a video setting isn't right, but all it was telling me with audio is "this is not an HD video." Kami

kj-radetski wrote on 7/23/2017, 5:01 PM

@johnebaker I did record the videos using Constant Framerate, because that is the default for OBS, and I didn't change that setting. I will send you what the video and audio screen look like on my recording software.

kj-radetski wrote on 7/23/2017, 5:06 PM

"A solution for future captures is to ensure the capture frame rate is constant - some capture programs will allow this, others have a setting for it to be constant, however they often aim to capture at this rate but drop the frame rate if they start struggling."

I understand this part, the part I don't understand is that it has never struggled before. This is the first time it has ever done this.

mike-weigel wrote on 8/2/2017, 7:40 AM

When I digitized video from my Canon HV40 i had some dropped frames. When I saw it, I stopped tape, rewound and recorded a few seconds before the frame drop. Now I need to resync the clips. Auto sync is not doing it. The waveform does not display information to line up the clips visually. Who else has this issue and how to solve it?