[Asterisk-video] aac audio

Sergio Garcia Murillo sergio.garcia at fontventa.com
Wed Apr 11 13:54:40 MST 2007


Yes, Francesco has been investigating that problem on audio (expecially on
Nokia handsets).
I think that the problem could be related with some small delay on app_play
that causes some
timing problems and makes the audio arrive late to the terminal.
As soon as I know something more I'll let you know, I don't have much free
time latelly
so mainly is just Francesco the one who is dealing with it.
By the way, i don't know if it would help, but the makefile was done without
optimization
(i think) so try recompiling everything with -O3 enabled to see if it help.

Greetings
Sergio Garcia

----- Original Message ----- 
From: "René van Weert" <rvweert at gmail.com>
To: "'Development discussion of video media support in Asterisk'"
<asterisk-video at lists.digium.com>
Sent: Wednesday, April 11, 2007 7:03 PM
Subject: RE: [Asterisk-video] aac audio


Hi,

I mistakenly used AAC indeed. I am now back to amr-nb which is working, but
not 100% correct.
I put up a sound sample of how it sounds on my Nokia N80 here:
http://www.digitalinteraction.nl/downloads/audiosample.mp3

Is it because there is still some work to do or because I am doing something
wrong the audio sounds so wrong?

I have used ffmpeg to convert my media file as follows:
ffmpeg -i woning2.wmv -ab 7.4k -ac 1 -acodec amr_nb -ar 8000 -vcodec h263 -r
10 -s qcif -b 46K -pass 1 -passlogfile log dest.mp4
ffmpeg -i woning2.wmv -ab 7.4k -ac 1 -acodec amr_nb -ar 8000 -vcodec h263 -r
10 -s qcif -b 46K -pass 2 -passlogfile log dest.mp4

mp4creator --hint=1 dest.mp4
mp4creator --hint=2 dest.mp4

The destination file is available here:
http://www.digitalinteraction.nl/downloads/dest.mp4
Mp4info gives:
Track   Type    Info
1       video   H.263, 77.500 secs, 44 kbps, 176x144 @ 10.000000 fps
2       audio   AMR, 78.240 secs, 8 kbps, 8000 Hz
3       hint    Payload H263-2000 for track 1
4       hint    Payload AMR for track 2

The audio does sound correct when played back on a pc.
I also tried with lower bitrates for both audio and video but without
result.

Any clues in what I'm doing wrong?
Thanks in advance.

René

-----Oorspronkelijk bericht-----
Van: asterisk-video-bounces at lists.digium.com
[mailto:asterisk-video-bounces at lists.digium.com] Namens Sergio Garcia
Murillo
Verzonden: donderdag 5 april 2007 12:48
Aan: Development discussion of video media support in Asterisk
Onderwerp: Re: [Asterisk-video] aac audio

Hi

Why do you need to use AAC?
You should use one of the codecs supported by asterisk, currently you can
use pmcu or gsm-amr (for using it with app_h324m).
I added an application a few days ago for creating an mpr4 file from a pcmu
file, you can find it here:

http://sip.fontventa.com/svn/asterisk/tools/pcm2mp4.cpp

Greetings
Sergio

----- Original Message ----- 
From: "René van Weert" <rvweert at gmail.com>
To: "'Development discussion of video media support in Asterisk'"
<asterisk-video at lists.digium.com>
Sent: Thursday, April 05, 2007 12:17 AM
Subject: [Asterisk-video] aac audio


Hi everyone,

I'm using app_mp4 right now and it is working great. The only problem I have
is that I cannot generate 8000hz AAC audio with my ffmpeg. I tried also
several different (precompiled) versions but without any luck. Ffmpeg only
accepts 11025hz or higher. Is there any other way to create the audio for
the mp4 file?

With kind regards,

René van Weert

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