[HELP] the AAC file export from WAV in Hybrid, in potplayer sound and picture out of sync

[ssdde]

when the AAC file exported from WAV in Hybrid, i played video and load the exported AAC in potplayer, but the sound and picture out of sync, how to solve?

[Selur]

Your audio needs to be synched to the video. Could be that a simple delay fixes the problem, could be that the audio/video is stretched, could be that the audio/video contains parts the other stream doesn't cover,..
No clue what you are doing and where the audio came from since it did not come with the video in the first place.
Hybrid allows to set a delay, but that delay will only have an effect when audio&video are put together into a file,... (Hybrid also allows to stretch/compress the audio)
Usually audio synching is done through NLE software,...

Cu Selur

[ssdde]

Your audio needs to be synched to the video. Could be that a simple delay fixes the problem, could be that the audio/video is stretched, could be that the audio/video contains parts the other stream doesn't cover,..
No clue what you are doing and where the audio came from since it did not come with the video in the first place.
Hybrid allows to set a delay, but that delay will only have an effect when audio&video are put together into a file,... (Hybrid also allows to stretch/compress the audio)
Usually audio synching is done through NLE software,...

Cu Selur

the aac filename exported by Hybrid is 123test_DELAY -43ms.aac, i only name it 123test.aac when save it, but the filename result is 123test_DELAY -43ms.aac

so it means Hybrid think it should be delayed -43ms automatically?


the WAV file is synchorize with video, i play video and load the wav track in potplayer, is OK.

but when i export the WAV to AAC in Hybrid, i play video and load the AAC track in potplayer, is out of sync.

[Selur]

If you feed Hybrid with a audio only source, Hybrid should not add any delay info to the output name, since there is nothing to delay the audio against.
If you feed Hybrid with an audio video source and extract the audio Hybrid will add the delay info noted in the container for audio/video synch.
Hybrid does not assume that anything happens automatically. It assumes that the delay info in the container is correct and thus is needed to keep the audio sync.
Note that when converting to aac the delay needed will change since aac encoders typically change the delay also depending on the output container delay might have to be adjusted again.
There were a few discussions about that over at doom9s years ago and I adjusted the code in Hybrid to automatically adjust the delay automatically.
So to really keep it totally sync you would have to do some math depending on the encoder settings and the target container.
-> Since you want to keep the audio separate your best best is probably take the -43ms as a starting delay and see if there's an option in the player you use to adjust the delay. Assuming there is one adjust it until it fits.

Cu Selur

[ssdde]

the WAV file is synchorize with video, i play video and load the wav track in potplayer, is OK.

but when i export the WAV to AAC in Hybrid, i play video and load the AAC track in potplayer, is out of sync.

then when i export the WAV to AC3 in Hybrid, i play video and load the AC3 track in potplayer, is OK.


it seems AAC need special setting or something?

but i want to encode new video with X264+AAC, not X264+AC3, is there anyway to solve?

if i encode the AAC with video by Hybrid, the result is automaticlly sync?

[Selur]

Like I wrote before encoding to aac will change the delay depending on the settings used.
Different audio formats have different latencies (https://en.wikipedia.org/wiki/Comparison...ng_formats)
The audio handling isn't that simple.

You could try whether enabling 'Config->Input->Decoding->Use delaycut to fix delays' (or 'Fix negative/positive delay through ffmpeg') before loading your source from which you extract the audio helps to generate a .wav and .aac output without delay,... (haven't used the option for years)

If that doesn't help you are on your own since I do not plan to search the net to find out all the dependencies again. (did that years ago to write the delay adjustment in Hybrid.


(Still don't get why you don't keep audio&video inside a container and need them separately and why you first extract the audio and the convert it later,... and the whole thing does not make any sense to me at all. )

Cu Selur

[ssdde]

the video is Madarin, and i find Cantonese track, but the sound in Cantonese some parts need to be enlarged or lower, also some parts in Cantonese need to be delele or adjust, not the whole Cantonese track,

but Hybrid only can grain or decrease whole track volume, so i have to deal the track with adobe audition, then export the lossless format WAV, play video with potplayer load the WAV for test, everything is OK,

then i need to encode the WAV with video, using X264+AAC, so i need to convert the WAV to AAC firstly, but when i play video with potplayer load the AAC for test, out of sync.

i thought encode the WAV with video, the result would be x264+WAV, now i realize i can encode the WAV with video, and choose AAC encoder, the result will be x264+AAC .



the update:
though it's out of sync that playing video with potplayer load the AAC for test, i encode the AAC with video by Hybrid directly, and the encoded video file is sync, everything is OK! no need to set anything, amazing!

so the AAC loaded in potplayer is out of sync, but encode the AAC with video, the result is sync.

[Selur]

Yes, Hybrid will do the necessary calculations to compensate the delays caused by the aac encoding.
As a side note: instead of Adobe Audition, you should use some NLE Software to keep audio&video present while changing the audio.

Cu Selur

[ssdde]

Yes, Hybrid will do the necessary calculations to compensate the delays caused by the aac encoding.
As a side note: instead of Adobe Audition, you should use some NLE Software to keep audio&video present while changing the audio.

Cu Selur

thanks for suggestion