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YouTube Audio problem

Posted by affter333 
Re: YouTube Audio problem
May 18, 2015 05:16PM
affter333 wrote:
-------------------------------------------------------
> so maybe 480p is AC3 or something
> that's not just 2 channel stereo ???

This is definitely NOT the case.
This is still AAC LC @128kbpsABR, SR=44.1kHz, ac=2 (stereo)
MediaInfo would have shown it if it was otherwise -
I have several files with AC3 encoding (AVI, MP4 but mainly MKV)
and MediaInfo always detects correctly the audio stream...

The following ffmpeg command extracts losslessy the audio stream
from your "dropbox" video file:
ffmpeg -i foo.mp4 -vn -c:a copy -f adts audio.aac
"foo.mp4" is your renamed file, for ease of use...
I have attached the ffmpeg extraction log,
where you can also see it reporting that:
Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s
The raw audio stream is then loaded fine on the lossless MP3/AAC
audio editor mp3DirectCut v2.20
See attached screenshot...

> but strange enough, the 360p version does have
> sound on my system, but not 480p ,

From your "youtube settings.jpg" screenshot I
can tell you are (still) on Windows XP and you
are using some codec pack (possibly K-Lite)
which contains ffdshow & MPC-HC - has this been
updated to a recent version?
Maybe you need to fine tune it better (via Codec
Tweak Tool?) - perhaps change the MP4 splitter
to Haali?

> but the 480p is complete blank, it seems that
> even goldwave can't get the audio from 480p.

In any case, as you know, the 360p file downloads
as a standalone MP4 one, while the 480p downloads
as individual dash streams that - according to user
setting - get muxed to MP4 via the internal, java based,
multiplexer. The devs themselves have said that this
is not the optimal solution, but works in 99.9% of cases.
Maybe your Goldwave editor (a payware I haven't tried)
doesn't like something in the MP4 headers of this
particular file - hard to tell...
FRD itself is a downloader, not a fully featured AV suite.
It creates FLV/MP4/TS files that usually work in decent
players for viewing and this is enough...
For further editing/manipulation of those files,
you are free to use the software of your choice...

If the MP4 container created by FRD doesn't
work well in Goldwave (and you must use this one),
I would suggest you demux both streams to raw ones
(you can use ffmpeg:
Video stream:
ffmpeg -i foo.mp4 -an -c:v copy -bsf:v h264_mp4toannexb -f h264 videoES.h264
Audio stream:
ffmpeg -i foo.mp4 -vn -c:a copy -f adts audioES.aac)
and then mux again to MP4 (or MKV) container
via another multiplexer - I personally use MP4Box,
but ffmpeg is simpler:
ffmpeg -i videoES.h264 -i audioES.aac -c copy -bsf:a aac_adtstoasc -f mp4 foo-remuxed.mp4).
If this new file doesn't work still, maybe contact
Goldwave, if a registered user...
I am putting this to rest now; so should you...

Regards to China?
Attachments:
open | download - Extraction.txt (1.2 KB)
open | download - AudioEditor.jpg (77.5 KB)
Re: YouTube Audio problem
May 22, 2015 04:15PM
tong2shot Wrote:
-------------------------------------------------------
> As stated in mediainfo (by me and TVjunkie) it's
> AAC and stereo, but the left channel is completely
> flat.
>
> Here is the waveform from audacity (sound editor)
> :
> [s15.postimg.org]
>
> So I think your video player and sound editor need
> to be updated smiling smiley

ok, thanks , my goldwave is like 5 years old, need to updated..
Re: YouTube Audio problem
May 22, 2015 04:17PM
yea I'm still on XP and my ffmpeg is pretty old too, need to update..
Thanks from taiwan..
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