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VLC conversion of .mp4 files working partially
Posted: 25 Feb 2022 00:03
by jalcaid001
Hi,
Sometimes I convert a file and the resulting file doesn't play for the first ~5 secs, like if there was a sync problem. Doesn't happen always. And some files that were converted correctly with 3.0.8 are not when I convert them again with 3.0.16.
Is this known? Any solution?
H264 + MPEG AAC mp4a (from a Samsung phone video camera)
Use profile: H.264 + MP3 (MP4): Video Same as source, Codec MPEG 4 Audio (AAC), 128 kb/s, 2 channesl 48000 Hz
Re: VLC conversion of .mp4 files working partially
Posted: 25 Feb 2022 11:21
by Lotesdelere
Re: VLC conversion of .mp4 files working partially
Posted: 01 Mar 2022 12:30
by jalcaid001
Nightly build didn't work
Anyway, I tried again with 3.0.8 and it works. But problem doesn't seem to be just the conversion. IT's the way VLC plays it.
I played the same converted videos with avidemux w/o problems.
Re: VLC conversion of .mp4 files working partially
Posted: 01 Mar 2022 16:13
by jalcaid001
When I convert with VLC to x264 with default parameters, I get files about 1/2 size . What is the equivalent in Avidemux?
Is the quality option I see equivalent to Avidemux Quantizer? IS it like Constant Quantizer in Avidemux (
https://www.avidemux.org/admWiki/doku.p ... rial:h.264)?
Re: VLC conversion of .mp4 files working partially
Posted: 02 Mar 2022 12:55
by Lotesdelere
Re: VLC conversion of .mp4 files working partially
Posted: 02 Mar 2022 17:59
by jalcaid001
I didn't see any CRF option on Tools -> Preferences -> Show settings: All -> Input/Codecs -> Video codecs -> x264 (similar entries to the image below)
Are you talking about 'video quality post processing level' ?
In anycase the quality factor may mean CRF (constant rate factor) or Cosntant Quantizier (per Avidemux options). Which one is VLC using?
Re: VLC conversion of .mp4 files working partially
Posted: 03 Mar 2022 13:37
by Lotesdelere
As I said in the threads I've mentionned, in VLC the CRF setting is named Quality-based VBR in Tools -> Preferences -> Show settings: All -> Input/Codecs -> Video codecs -> x264.
Re: VLC conversion of .mp4 files working partially
Posted: 04 Mar 2022 16:56
by jalcaid001
Oh... I realized what I was missing.. I had to do 'Show All' to see the option you were talking about.
I have been playing with it and perhaps I found I bug (or I'm missing something). LEt me explain:
Original file: 19Mb
I reset preferences on VLC, Quality-vased VBR = 23
I encode and I get a file of ~8k. About what I get with Avidemux
I change preferences to Quality-vased VBR = 22. I get 22MB (way too big !)
I change preferences again to Quality-vased VBR = 23. I get 19MB (way too big !)
al
So it looks some other parameter is being changed when I change 'Quality-vased VBR'. I went through all parameters on Input/Codecs -> Video codecs -> x264 and I didn't see a difference.