So i have stumbled across something thats extremely weird. Lets say you take a prores File, for example this one: and you convert it to h264 using lets say ffmpeg/shutter encoder. you then import that back into flame and boom its off by 1 frame [image] but then… I import both clips…

A few years ago we ran into this issue with our audio department seeing our MP4s out-of-sync. We found the Apple Dev article and a little more from what I remember. I believe now, MP4s have a value set for audio priming in the MP4’s header. But Apple didn’t write QTKit/QuickTime 7 to read this val…

Trying again to find better more constient files to test with: here you can download the files: https://replayboys.fromsmash.com/soudnsyncTEST Flame does this, everthing fine except the one created by ffmpeg. [image] Resolve, everything fine except the one created by flame [image] In FCPX a…

I think its due to THIS Audio Priming - Handling Encoder Delay in AAC Describes the file format and internal data structures of QuickTime movies. Basically AAC by design uses PRIMED samples , so bascially a bit of preroll or something like that for reasons,…

Could this be related? [image] MP4 audio from AME is off by a quarter frame Tools and Tech It appears that any AAC audio exported from Adobe Media Encoder is off by about 10 ms / 575 samples / a quarter of a frame. Apparently, this has been a thing for at least five year…

totally thats exactly why we found it. Client complaint about async sound - Audio is blaming us because they ingested a mp4/aac and compared to their pcm/wav file in proTools. Its not a AME problem per se bur rather flame not decoding correctly. Or ame not setting the correct metadata - potato …

Can you use ProRes or dnxhd for rough cuts to get around this?

its a AAC audio thing so you can also use .mov h264 which supports PCM/WAV audio… or anything else, problem is what file is the one that every pc/mac/whatever can open natively? h264 mp4 with aac audio… mp4 h264 does not support PCM audio even though apparently it SHOULD since 2020 … and in the e…

i love this kinda stuff and its a great feeling to be able to somewhat crack this. Good to know that aac can be async depending on the encoder and decoder combo used and there is nothing much we can do.

Hi Finn, I made some tests too and it looks like, that each software is dealing different with the delay of compressed audio. I used a Prores as a base and encoded MP4s via Adobe Media Encoder, Shutter Encoder and Handbrake and imported these files to Adobe Audition and Audacity. In Audacity: Pr…

cool thanks for confirming my findings thats awesome!!

thank you so much, thats great info, at least we stumbled across the same issues all seperately :slight_smile: Its really extremely good to know whats what, and if I know see aac audio beign not sync I know what to say and do , cheers man! +1 on the FLAC part, also PCM audio in mp4 has been standa…

Weird h264 Audio behaviour

Flame Flame Questions

KuleshovEffect December 7, 2022, 5:39pm 4

Could this be related?

-Ted

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Weird h264 Audio behaviour

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