Video with 48 kHz audio

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p8guitar
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Video with 48 kHz audio

Post by p8guitar »

I cannot play a video that has 48 kHz audio in sync. The audio plays too slow and gets behind the video time. And as soon as I play the 48 kHz clip, Resolume doesn't use my external fireface audio device any more but switches to the internal Realtec audio device.
?!?
the audio track of the video is shorter than the video, there is no audio at the end. Is this the problem? Does Resolume try to stretch the audio so that it fits the whole length of the video?
Video with 48 kHz audio.jpg
Video with 48 kHz audio.jpg (8.77 KiB) Viewed 7010 times

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Arvol
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Re: Video with 48 kHz audio

Post by Arvol »

48,42.1,88.2,192. It shouldn't matter, that's just the sample rate. I've used many sample rates no issues. I would be willing to bet a beer that the problem you are having is that your clip is not DXV3 and is mp4. open up Alley on your computer remux the video to DXV3 and I bet that will get you up and running.

p8guitar
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Re: Video with 48 kHz audio

Post by p8guitar »

That was worth a try, I converted the video with alley to dxv, with the same audio sample rate 48 kHz. But same problem. Then I converted the sample rate to 44100 Hz, but this didn't help neither.

Now I noticed that the audio ends at the very end of the video, when I play it in Resolume. But actually it should end about 20 seconds before the video ends!

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Arvol
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Re: Video with 48 kHz audio

Post by Arvol »

Sounds like it's an issue with the file. Maybe re-render it (if possible) but render it from whatever compositing software you have using the DXV3 codec (works for Adobe products).

Does the audio play differently in Resolume than it does in other software like VLC?

Same rates won't change the start and end time of the audio, it's just on how much "detail" is in the audio.
The waveform will be the same length in whatever sample rate you are using, it's just how many samples or detail is pulled from each waveform that is changed by the sample rate. Here's a visual guide to help understand what the sample rate is grabbing from the waveform:
Image
Think of the blue line as an old record, and then if you are recording that record into your computer digitally, the sample rate will be how many samples ro details you care grabbing from the original analog signal. so the blue signal is pure non digital analog audio, and then the lines inside it are the digital representation of that audio but in digital form. the higher the number the more those bars will form a natural curve like a smooth sinewave.
TBH 44.1 and 48 are perfectly fine compared to 192. I've worked in million dollar recording studios and have played back 44.1 vs 192 and it's really not that much of a change in quality (especially for what people are listening on these days, like earbuds and cell phones). 88.2 was my go to, but for anything live like concerts 44.1 or 48 is perfectly fine. 48 seems to be the standard these days (it has been for a long time for film).

sorry for the rant lol

Zoltán
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Re: Video with 48 kHz audio

Post by Zoltán »

p8guitar wrote: Tue Nov 17, 2020 20:55 the audio track of the video is shorter than the video, there is no audio at the end. Is this the problem? Does Resolume try to stretch the audio so that it fits the whole length of the video?
Video with 48 kHz audio.jpg
When you combine separate files into a single clip, the video speed will be changed to match the audio duration. Should not happen with a single file though.
Which program created this file?

Could you share the file so we can take a look?
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p8guitar
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Re: Video with 48 kHz audio

Post by p8guitar »

To create the file, I did these steps:
- recorded the output of Resolume via Spout with OBS on a Windows machine (mp4 x264)
- opened this file on a Mac with the Quicktime Player 7 app (7.6.9) and
1. trimmed the length
2. deleted the audio track which was recorded from Resolume
3. added another audio file
4. converted to mp4 with settings suited for youtube (PCM audio with 44,1 kHz->AAC audio with 48 kHz)

Today I shorteden the video to 4'25, so that the video and the audio track have the same length. This solved the problem, it plays in sync now.
Here are the links:
original file
https://1drv.ms/v/s!AsNedAPvuG2thSursGM ... I?e=H14c0d
shortened file (play in sync):
https://1drv.ms/v/s!AsNedAPvuG2thSxM3ih ... d?e=9HxPtM

the original file doesn't play in sync with Alley and Resolume, but it plays in sync with all other apps that I use. Windows: Film & TV app and Windows Media Player. Mac OS: Apple Quicktime 7 and IINA.

p8guitar
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Re: Video with 48 kHz audio

Post by p8guitar »

Arvol wrote: Wed Nov 18, 2020 00:59 ...88.2 was my go to, but for anything live like concerts 44.1 or 48 is perfectly fine. 48 seems to be the standard these days (it has been for a long time for film).

sorry for the rant lol
I record with 24bit (and master to 16 bit of course), but I never bothered to raise the sample rate. I think I don't have the ears and the equipment to hear the difference, and the hard disk will fill much faster, too... ;)
I think 48 kHz is usually used for video production, and 44,1 kHz for audio production. But I try to keep the 44,1 kHz in video and audio until the last step when I convert to youtube specs.

Zoltán
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Re: Video with 48 kHz audio

Post by Zoltán »

Thanks for the files.
Made a ticket, we'll check if we can fix this!
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