Video decoder

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Tue, 2005-12-13 12:01
Omino delle lego
Joined: 2005-12-13
 Forum posts: 3
Hi everybody,

I have to develop a video decoder (H.264) for Symbian based phone. If I develop using the format decoder plugin do I need to write also the controller plugin (and also the source and the sink) or can I "link" my decoder to a controller provided by Symbian?
The other solution is to write the decoder for DSP processor. I wonder if every phone as the dual core architecture with the DSP and where can I find the documentation to understand how to do this.

Many thanks in advance

Alessio

Tue, 2005-12-13 13:05
groys-forum
Joined: 2005-11-10
 Forum posts: 10
Re: Video decoder
Firstly I hope you have a H.264 decoder code already in software or hardware. If not then writing a decoder itself is a humongous job.

Assuming you have a software decoder or aim to work on a nokia phone which supports H.264
refer to
http://forum.newlc.com/index.php/topic,11753.0.html

Quote
If I develop using the format decoder plugin do I need to write also the controller plugin (and also the source and the sink) or can I "link" my decoder to a controller provided by Symbian?
A controller plugin is the only necessary plugin. Linking it to an existing controller provided by symbian is very difficult assuming u have sdk or devkit. the examples are trivial for audio n non-existent for video.

Quote
The other solution is to write the decoder for DSP processor. I wonder if every phone as the dual core architecture with the DSP and where can I find the documentation to understand how to do this.
This is the type that is there in nokia phones with mmf support. However there is negligible documentation on making such a plugin. If you r working on nokia phones which support h.264( i dont know abt the phones)  then it might be possible after a great deal of effort.

hope this helps
groys
 
Fri, 2005-12-16 12:21
Omino delle lego
Joined: 2005-12-13
 Forum posts: 3
Re: Video decoder
Many thanks Groys.

I have one more question. It's possible to write just the controller (and not the player) and let Symbian to manage it when is necessary (e.g. when streaming a h.264 video), and how?

thanks
 
Fri, 2005-12-16 13:44
groys-forum
Joined: 2005-11-10
 Forum posts: 10
Re: Video decoder
Hi,
you look a little confused. If your aim to stream video then you do not need the extend the mmf framework provided your nokia phone has plugins for playing h.264 video. Read the document on creating video applications in c++ carefully. Also these two documents
Video_And_Streaming_Content_Creation_Guide_v1_1_en.pdf
and
Video_And_Streaming_In_Nokia_Devices_v2_0_en.pdf
might help. Read them carefully. Also there are quite a few queries on streaming video on this forum and forum nokia refer to them.

I am not sure mmf framework is used in video streaming. In audio streaming it is not.

Quote
It should be noted that unlike many of the other multimedia framework (MMF) APIs in Symbian OS v7.0s the streaming utility does not make use of MMF controllers or the MMF controller framework. It interfaces directly with the MMF DevSound layer which is the highest level abstraction for the sound device itself. This allows for very low-latency audio processing to be performed without the overhead of the MMF or the MMF plugins.
from Audi0StreamSymbianOSv1.1.pdf.

If the phone does not support H.264 then you will have to probably use a software decoder and it is extremely difficult to extend mmf to do that as there is no existing example of such a thing.
do let us know how it goes
regards
groys
 
Fri, 2005-12-16 14:04
groys-forum
Joined: 2005-11-10
 Forum posts: 10
Re: Video decoder
Hi and regarding ur query
Quote
It's possible to write just the controller (and not the player) and let Symbian to manage it when is necessary (e.g. when streaming a h.264 video), and how?

if u have a player written based on mmf then u only need to write the plugins correctly and the player will detect ur plugin automatically. i.e. if video player on nokia phones use mmf then ur plugin will be automatically used to play the h.264 file.
regards groys
 
Sun, 2006-04-30 13:01
brianpo
Joined: 2006-04-25
 Forum posts: 1
Re: Video decoder
i want develop the video player H264
but i don't know , what is my start point?

can anyone give me suggestion?
 
Mon, 2006-06-26 09:49
winstonma
Joined: 2006-02-21
 Forum posts: 14
Re: Video decoder
I already ported a H.264 decoder on Symbian and tried those. Unfortunately the performance on Symbian is extremely slow (it's about 10-12 times slower than the H.263 decoder that I ported). I can only get as much as 8fps with H.264 but more than 40 fps with H.263. You really need to evaluate your decoder performance before you port it. Otherwise I'll be a waste of time.

Does any know which open-sourced H.264 decoder is with good performance?
 
Wed, 2006-06-28 16:42
kundutech
Joined: 2005-01-13
 Forum posts: 31
Re: Video decoder
Hi winstonma + all
Well H.264 isn't the easiet codec is it. Yes your performance will be crap, specially compared to H.263, which is a crap format it self, but not that computation intensive.

Now what size (SQCIF?) did you use for H.264?

PS. There are phone coming with H.264 support, SW and maybe HW in the future

http://www.kundutech.com

 
Wed, 2006-08-16 04:30
winstonma
Joined: 2006-02-21
 Forum posts: 14
Re: Video decoder
QCIF format... I ported JM H.264 codec... but if you use ffmpeg then I think it can be as fast as 30fps on Symbian... but so far I haven't read the code from ffmpeg... but as I hear the porting is much much harder than JM
 
Fri, 2007-02-02 09:50
xuepomh
Joined: 2007-01-31
 Forum posts: 2
Re: Video decoder
Hi,I just want to develop a H263 video decoder.But I've idea about how to start?Can anyone give me some infomation about it?
 
Wed, 2007-02-14 13:04
kota
Joined: 2006-07-26
 Forum posts: 42
Re: Video decoder
hi, i am looking for an example code of video controller plugin.

any help?
 
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