[Asterisk-video] aac audio

Thu Apr 12 11:39:12 MST 2007

Hi Francesco and Sergio,

Thank you both for the advice. I tried now with audio at 12k and video at 50k. I also recompiled with -O3. On other phones the sound is better already but on my nokia n80 it still is a little blurry. Ff I turn of sending video and audio from the phone however the incoming audio quality improves quite a lot. Might this be something related to the problem?

With kind regards,

René

-----Oorspronkelijk bericht-----
Van: asterisk-video-bounces at lists.digium.com [mailto:asterisk-video-bounces at lists.digium.com] Namens francesco
Verzonden: donderdag 12 april 2007 9:59
Aan: Development discussion of video media support in Asterisk
Onderwerp: RE: [Asterisk-video] aac audio

Hi Renè,

Try to hint audio track indicating also payload size:

mp4creator --hint=2 -mtu=64 dest.mp4

I suggest you also to follow Sergio tip to compile with -O3 option. You
may also use amr mode 8, with ffmpeg option -ab 12K...lowering bit rate
doesn't give me any result, so I don' t think it is a good choice.

Quality should be much better. But still not good in Nokia N80 as in
other handset.

I'm working on it and let you know as soon as I have news.

Greetings 
Francesco

On Wed, 2007-04-11 at 19:03 +0200, René van Weert wrote:
> 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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-- 
Francesco Emmi  
A-Tono
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