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Gmane
From: Chris Purves <chris <at> northfolk.ca>
Subject: Re: working with Canon avi's
Newsgroups: gmane.comp.video.transcode.user
Date: Thursday 20th April 2006 01:31:33 UTC (over 10 years ago)
Eric Lavarde - ASB wrote:
> Hi,
> 
>> On Mon, 17 Apr 2006 10:22:06 +0800
>> Chris Purves  wrote:
>>
>> [...]
>>> Yes, I see that if I try to encode as mp3 and leave encoding framerate
>>> as 11024.  If I use -E 11025 I don't get the error, but the audio
>>> doesn't work.  Using -E 44100,16,2 gets me usable audio, however.
>>>
>>> I still can't encode to PCM, which is one of the items on your bug
list.
>> Interesting. I think this issues are related, but I'm still
investigating.
>> After very first tests, I can't reproduce yet reproduce this
misbehaviour
>> using some MJPEG/PCM/AVI samples taken from my tv-tuner card.
> it might be due to the 8 bits, testing showed me that 22050 is needed as
a
> minimum for MP2/3 kind of sound, but also that 16 bits per sample are
> required for PCM (neither mplex nor lavaddwav do accept 8 bits, even
> though they might accept 11025Hz)
> In other words, you need at least -E 11025,16; if not even -E 22050,16
> 
Ah hah!  It is the 8 bits that is the problem.  If I use the command:

transcode -i test_in.avi -o test_out.avi -y ffmpeg -F mjpeg -N 0x1 -E 
11024,8,1 -f 0,5

I see the following output:

[transcode] A: import format    | 0x1     PCM          [11024, 8,1]   88 
kbps
[transcode] A: export format    | 0x1     PCM          [11024, 8,1]   88 
kbps

but tcprobe says the bitrate is 176 kbps and if I play back it's 
ear-piercing static.

If I encode to 16 bit using the command:

transcode -i test_in.avi -o test_out.avi -y ffmpeg -F mjpeg -N 0x1 -E 
11024,16,1 -f 0,5

I see this output:

[transcode] A: import format    | 0x1     PCM          [11024, 8,1]   88 
kbps
[transcode] A: export format    | 0x1     PCM          [11024,16,1]  176 
kbps

tcprobe reports 176 kbps and the audio is normal.


-- 
Good day, eh.
Chris
 
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