Author Topic: Audio Delay On MP4 File  (Read 207 times)

melh23

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Audio Delay On MP4 File
« on: September 21, 2017, 04:46:49 AM »
I have an MP4 file that I have edited. I am also trying to delay the audio 400ms. The audio disappears. 250 ms works. Am i doing something wrong?

Settings

Video Output
   Mpeg4 AVC (x264)
   Filters
      Crop Right 13 Left 8 Bottom 33
Audio Output
   AAC (Faac)
   Shift 200 ms (Taken as Delay I guess. Matches VLC Audio Delay which is Plus to for HULU
Output Format
   MP4 Muxer
« Last Edit: September 21, 2017, 04:50:01 AM by melh23 »

AQUAR

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Re: Audio Delay On MP4 File
« Reply #1 on: September 21, 2017, 07:30:11 AM »
I often find that audio shifts are reported with different values.
Mediainfo never matches up with set audio shift values in ADM.

I do get a fair match between VLC and ADM settings.
Positive values mean delaying sound     

eumagga0x2a

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Re: Audio Delay On MP4 File
« Reply #2 on: September 21, 2017, 08:31:22 PM »
I have an MP4 file that I have edited. I am also trying to delay the audio 400ms. The audio disappears.

What do you mean by "disappears"? Does the saved video lack an audio track completely? Detected by which application? Is the issue specific to the FAAC encoder? (Hint: other AAC encoders are better.)

melh23

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Re: Audio Delay On MP4 File
« Reply #3 on: September 21, 2017, 11:35:08 PM »
Playing Video in VLC there is video but silence for audio.

eumagga0x2a

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Re: Audio Delay On MP4 File
« Reply #4 on: September 22, 2017, 06:30:05 AM »
Please launch Avidemux, load the source file, encode it as above, then compress and attach admlog.txt accessible via the "Help" menu. In the next step please load the resulting video and copy to clipboard and paste in your reply the info shown by Avidemux (Alt+Enter).

xtro

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Re: Audio Delay On MP4 File
« Reply #5 on: October 07, 2017, 10:35:04 AM »
Extract the audio as raw to remove the header using Yamb portable for example. You might want to check, if it has been normalized correctly or has any clipping by using Mp3 Gain with aac gain tool renamed to mp3.exe so it works inside the gui. If this fails to check you might have an iso incompatible audio track which is causing you problems e.g too wide variances using vbr, if your track is vbr?

If all is well, then place the original file in mkv toolnix. Disable the original aac track. Drag the extracted mp4 raw audio to the video input box. Highlight this new audio and on the right side you will see audio delay. Enter -400 and mux away!