Hi,

Does anyone know if the H.264 decoder and encoder in the N900 makes use of the DSP of the OMAP3430? The OMAP3430 is quite powerful when it comes to video encoding and decoding, if used correctly you can decode and encode 24fps QVGA h.264 simultaneously, in real time. This could be useful for video calling. However, this only works if you make use of the DSP. It would be a shame if the N900 just uses ffmpeg via GStreamer and does everything on the ARM core.

If the N900 does everything on the ARM core, we should keep an eye at the upcoming Droid phone, which as well uses the OMAP3430 with Android. It can be expected that the Droid phone will use the DSP for video decoding and encoding. It should be quite easy to use the video codec from Droid in maemo. At a low level (underneath the OpenCore Multimedia framework) Android uses OpenMAX to interface to the codec. In theory it should be possible to directly use the codec in maemo via gst-openmax.

At this point it is unclear if the codec used in Droid will be open source. It could very well be that they supply a binary blob, in which case it wouldn't be as desirable to use it in maemo.

Yes, my understanding is that they do use the DSP.

Take a look in /lib/dsp/

e.g. h264vdec_sn.dll64 & h264vend_sn.dll64

So which players (built-in video player, mplayer, vlc) are able to offload some of the decoding work to the DSP? Does the DSP offer any hardware acceleration for decoding other formats than H.264, say MPEG2?

http://zaheer.merali.org/articles/20...erated-theora/

Droid does have the same chipset, but:

1. Does not play vids above 640X480 (I have a bunch but could not find any that work).
2. Locks the device up sometimes if higher bitrate or res. I have never locked the G1 up trying to play the same videos- They did not play either, but would at least just play audio or not play at all- no lock ups- ever.
3. Lower res 4:3 vids scale to fill top and bottom of scrren, but wide screen vids do not.

Droid is surprisingly weak in playing mp4 unless you follow specific parameters- just like the G1.

My guess this is due to Androids strict framework. No way to improve it unless Android adds it.

Sad that the device plays vids not much better than the G1.

Android as hole is rather rubbish at any type of media, it's still on the Google programmers 'to do' list apparently

The official firmware accelerates mpeg4, h264 and h263 with dsp. All gstreamer based apps can use it including default media player and zoutube.

Mplayer and vlc does not offload anything to the dsp.

I know this is a very old thread but since my question is related to the topic, I'll just post my question here -
Does N900 allow for sharing hardware decoder between 2 applications simultaneously? Also can 2 instances of the decoder be created by an application?

what about Youtube video decoding via Flash?