Acceleration in our pockets

Fri Jun 13 16:56:03 CEST 2008

Op Friday 13 June 2008 11:04:13 schreef Carsten Haitzler:
> On Fri, 13 Jun 2008 07:37:39 +0000 (GMT) David Samblas Martinez
>
> <dsamblas at yahoo.es> babbled:
> > Hi Raster,
> >
> > Your are not wrong at all about resolutions maths and bus bottlenecks, I
> > have learned a lot from your posts , and I'm very thankful for you effort
> > to communicate this to us.
> >
> > Nevertheless I think you were wrong about the pessimistic approach, "no
> > decent video from sd" . You have never said this explicit but some post
> > destilate such idea(at the end of this message I have extract some of
> > them) balrog have said it has pass over the 21 fps in 320x240 barrier 
> > (not clear if he had tried from sd yet) so maybe wrong is a strong word
> > (I don't thing so, but you may find it offensive) but don't confuse it
> > with lie that is really a strong word and I have never pretend to
> > insinuate this.
> >
> > And again I was thinking loud, and I was think I have erase this sentence
> > that have irritating you, again and again and again please accept my
> > apologizes
>
> no problems. what i don't want is people to get their hopes up. this was in
> the context of people asking if they can play vga video and me going "good
> luck!". there is reality - and you can sit and hack away spend lots of time
> and get 1 case to work, and work well. as i said - it will depend on codec,
> bitrate, quality etc. mpeg4 decode in hw is great - but remember it is also
> limiting to just mp4 - all your mpeg1, ogg, etc. videos will not work. also
> as long as mplayer is accessing glamo hardware it must run as root.
> admittedly we run everything as root - but come the day when we don't...
> this is trouble.
>
> as i said - it is possible within limits. the limits of using a software
> codec in mplayer (for example) in the example mp4 video i used @ 320x240
> was 21fps from flash, 19fps from sd card. :) in reality most phones don't
> really play any or much video beyond qvga anyway - so it's within ballpark.
> some do do better, but most don't.
>
> i just don't want people to be more optimisitc than they should be - i want
> you to be pleasantly surprised rather than bitterly disappointed. which do
> you prefer - use to tell you all sorts of things and then find they aren't
> possible, or us tell you it's unlikely/not so great, you buy anyway, and
> find it's better than we said? i suspect the 2nd case is one where you will
> keep coming back and be a loyal customer as we are (brutally) honest with
> you. i would have serious moral issues in telling you anything i didn't
> sincerely believe is the truth :)
>

Of course I'm happy we're being told the truth.

The things as I understand them from these mails and the archive (Yes, I've 
found the gmane archive with the search function :) ):

-The hardware is capable of copying an mpeg4 stream right from the sd-card to 
the glamo (DMA), but this is not easy and there is no software to do that. 
What is even easier is copying the mpeg4 stream through the CPU to the glamo. 
Since an mpeg4 stream uses much less than 7Mbit/s, this is no problem for the 
bus. The cpu doesn't have to decode anything, so even an almost chocked bus 
doesn't hurt. Of course the bus doesn't get chocked by 2x the same mpeg4 
stream.

-The software isn't capable of instructing the glamo to decode the mpeg4 
stream. To make such software the NDAd data sheet is needed, and OM isn't 
going to make it. Mplayer can send an mpeg4 stream to the glamo, but this is 
experimental and needs to be done as root.

I'm still confused about the clame somebody made he had sent a 320x240 mpeg4 
stream to the glamo and got 21fps when the data came from internal flash 
while the same stream from sd gave 19 fps. <my comprehension>. I assume the 
data HAS to pass the cpu when it comes from internal flash, because the flash 
and the glamo are on a different bus. When the stream came from the sd card 
it passed the graphics bus twice because dma doesn't work. A well compressed 
320x240 mpeg4 stream takes 500kbit/s max with sound. So twice this doesn't 
chocke any bus. The cpu also has time enough to do other things here.</my 
comprehension</a> So how could these framerates be so low? The site of the 
glamo claims it can do 30fps on VGA. Which maybe brings the needed bus speed 
to 1Mbit/s in the worst case with dma and 2Mbit without.

Peter

> > [...]> > > with the glamo you need to be careful what you do
> >
> > > > and how you do it. if you can
> > > >
> > > > > keep something entirely within the glamo - it
> > > >
> > > > should be ok. so things like
> > > >
> > > > > uploaded pixmaps and then blitting them around is
> > > >
> > > > ok. video decode is another
> > > >
> > > > > matter entirely. the glamo has an mpeg4 decoder on
> > > >
> > > > it - but we don't have any
> > > >
> > > > > api to access that directly/sanely and just feed
> > > >
> > > > it an mpeg4 stream. any other
> > > >
> > > > > codec has to be done on the cpu anyway and
> > > >
> > > > uploaded across the bus as yuv data.[...]
> >
> > [...]that is quite possible. 320x240 video would be sane possibly if the
> > source is internal flash instead of SD or maybe 802.11.[...]
> >
> > [...]but the problem here
> > is that xv does not provide a way to do this sanely (stream just mpeg4
> > data to x so it decodes in hardware). the graphics chip (glamo) can
> > decode mpeg4 itself, but we dont have the time or resources to do this
> > properly ourselves. you are free to do it yourself as we provide all the
> > code, but you would need to reverse-engineer the graphics chip or hope
> > that graphics documentation can be made public. right now you need an NDA
> > to see the docs.[...]
> >
> > [...]what freerunner *IS* good at is nice high resolution still images.
> > it is NOT good at motion (animation). that's possibly the simplest way i
> > know to describe its graphics :) great for ebook and text reading. great
> > for your high-res photos. don't expect a media-center out of it with
> > swooshy bits and fanciness and video at wonderful quality and resolutions
> > and framerates.[...]
> >
> > [...]see my other mail. 320x240 at 30fps is not possible. off sd card about
> > 19fps is the limit @ 320x240. 21fps if from internal flash. i did actual
> > tests. mpeg4 video.[...]
> >
> > --- El vie, 13/6/08, Carsten Haitzler <raster at openmoko.org> escribió:
> > > De: Carsten Haitzler <raster at openmoko.org>
> > > Asunto: Re: Acceleration in our pockets
> > > Para: dsamblas at yahoo.es, "List for Openmoko community discussion"
> > > <community at lists.openmoko.org> CC: "David Samblas Martinez"
> > > <dsamblas at yahoo.es> Fecha: viernes, 13 junio, 2008 2:47
> > > On Thu, 12 Jun 2008 19:22:30 +0000 (GMT) David Samblas
> > > Martinez
> > >
> > > <dsamblas at yahoo.es> babbled:
> > > > Hehehe definitively you have something to say :)
> > > > oops I thought that I have erased this final this so
> > >
> > > unfortunate sentence  so
> > >
> > > > please accept my apologizes lets joy the fact that the
> > >
> > > glamo will not be a
> > >
> > > > wasted chip
> > >
> > > it never was wasted, but it's not the ultimate solution
> > > to everything either.
> > > i'm still wondering where i was so "wrong"?
> > >
> > > > --- El jue, 12/6/08, Carsten Haitzler
> > >
> > > <raster at openmoko.org> escribió:
> > > > > De: Carsten Haitzler <raster at openmoko.org>
> > > > > Asunto: Re: Acceleration in our pockets
> > > > > Para: dsamblas at yahoo.es, "List for Openmoko
> > >
> > > community discussion"
> > >
> > > > > <community at lists.openmoko.org> CC:
> > >
> > > "David Samblas Martinez"
> > >
> > > > > <dsamblas at yahoo.es> Fecha: jueves, 12
> > >
> > > junio, 2008 6:58
> > >
> > > > > On Thu, 12 Jun 2008 14:52:07 +0000 (GMT) David
> > >
> > > Samblas
> > >
> > > > > Martinez
> > > > > <dsamblas at yahoo.es> babbled:
> > > > >
> > > > > nb - i codec only - and i also used mplayer at
> > >
> > > the time.
> > >
> > > > > mpeg1, mpeg2, not to
> > > > > mention a myriad of other codecs won't work
> > >
> > > there, and
> > >
> > > > > it still only producing
> > > > > qvga video.
> > > > >
> > > > > if you do follow prior threads on this, you will
> > >
> > > notice
> > >
> > > > > that i never covered
> > > > > the mp3 decode of the glamo. that's always
> > >
> > > possible,
> > >
> > > > > but as such to do well
> > > > > would need a generic codec-level api supporting
> > >
> > > it - like
> > >
> > > > > openmax.
> > > > >
> > > > > > I copy & paste an very interesting
> > >
> > > comment from
> > >
> > > > > balrog ,seems that I have
> > > > >
> > > > > > become his(totally voluntary) mail list
> > >
> > > assistant ;)
> > >
> > > > > > Rasterman..... 352x288 25 fps..... something
> > >
> > > to say?
> > >
> > > > > > --------------Begin of
> > >
> > > comment-----------------------
> > >
> > > > > > #  balrog Says:
> > > > > > June 11, 2008 at 4:20 am
> > > > > >
> > > > > > Mikko: I hope we’ll eventually see more
> > >
> > > than just
> > >
> > > > > MPEG support on the Glamo
> > > > >
> > > > > > (3D stuff etc). Regarding QVGA at this
> > >
> > > moment it’s a
> > >
> > > > > conjecture… and at this
> > > > >
> > > > > > moment it’s confirmed. I’ve just tried
> > >
> > > QVGA and
> > >
> > > > > while the colours became a
> > > > >
> > > > > > bit undersaturated and gamma seems to be too
> > >
> > > high, I
> > >
> > > > > got full 25fps playback
> > > > >
> > > > > > both straight and with rotation, hw-scalled
> > >
> > > from
> > >
> > > > > 352×288 to 240×320 or
> > > > >
> > > > > > 320×240. Unfortunately tslib seems to not
> > >
> > > have
> > >
> > > > > noticed the change and still
> > > > >
> > > > > > reports touch coords in 0…640 range.
> > > > > >
> > > > > > i_m_bison: Darude_-_Feel_the_beat.mp4 (the
> > >
> > > video is
> > >
> > > > > ok, the music not so
> > > > >
> > > > > > much:))
> > > > > >
> > > > > > tuXXX: I was wondering about that too, but
> > >
> > > rather MPEG
> > >
> > > > > decoding on the CPU
> > > > >
> > > > > > and scaling/rotation on Glamo - this would
> > >
> > > allow us to
> > >
> > > > > do more stuff
> > > > >
> > > > > > concurrently. The other way, as Mikko notes
> > >
> > > you
> > >
> > > > > transfer the video to the
> > > > >
> > > > > > VRAM, then back to the RAM and then back to
> > >
> > > the VRAM
> > >
> > > > > and the bus becomes a
> > > > >
> > > > > > bottleneck. In the current setup and normal
> > >
> > > usage I
> > >
> > > > > don’t agree with Raster
> > > > >
> > > > > > that 7M/s is a bottleneck, it’s rather
> > >
> > > hard to
> > >
> > > > > saturate with normal X usage
> > > > >
> > > > > > even coupled with SD card traffic etc.
> > > > > > ----------End of
> > >
> > > comment------------------------------
> > >
> > > > > > Raster, I'm really happy that you where
> > >
> > > so wrong
> > >
> > > > > at this topic
> > > > >
> > > > > > --- El jue, 12/6/08, Joerg Reisenweber
> > > > >
> > > > > <joerg at openmoko.org> escribió:
> > > > > > > De: Joerg Reisenweber
> > >
> > > <joerg at openmoko.org>
> > >
> > > > > > > Asunto: Re: Acceleration in our pockets
> > > > > > > Para: community at lists.openmoko.org
> > > > > > > CC: "Peter Nijs"
> > > > >
> > > > > <peter at familienijs.be>
> > > > >
> > > > > > > Fecha: jueves, 12 junio, 2008 2:37
> > > > > > > Am Do  12. Juni 2008 schrieb Peter
> > >
> > > Nijs:
> > > > > > > > Isn't the shared bus an
> > >
> > > advantage
> > >
> > > > > because now it
> > > > >
> > > > > > > can use DMA? Maybe that's
> > > > > > >
> > > > > > > > why
> > > > > > > > it is possible to hook up an
> > >
> > > sd-card to the
> > >
> > > > > glamo
> > > > >
> > > > > > > anyway. I see no other
> > > > > > >
> > > > > > > > explanation why one would put an
> > >
> > > sd
> > >
> > > > > cardreader in a
> > > > >
> > > > > > > graphics ship. Please
> > > > > > >
> > > > > > > > tell me if and why I'm wrong.
> > > > > > > >
> > > > > > > > Peter
> > > > > > >
> > > > > > > Good point. Would make perfect sense...
> > >
> > > /j_______________________________________________
> > >
> > > > > > > Openmoko community mailing list
> > > > > > > community at lists.openmoko.org
> > >
> > > http://lists.openmoko.org/mailman/listinfo/community
> > >
> > >
> > >
> > > ______________________________________________
> > >
> > > > > > Enviado desde Correo Yahoo! La bandeja de
> > >
> > > entrada más
> > >
> > > > > inteligente.
> > >
> > > _______________________________________________
> > >
> > > > > > Openmoko community mailing list
> > > > > > community at lists.openmoko.org
> > >
> > > http://lists.openmoko.org/mailman/listinfo/community
> > >
> > > > > --
> > > > > Carsten Haitzler (The Rasterman)
> > > > > <raster at openmoko.org>
> > > >
> > > >       ______________________________________________
> > > > Enviado desde Correo Yahoo! La bandeja de entrada más
> > >
> > > inteligente.
> > >
> > > > _______________________________________________
> > > > Openmoko community mailing list
> > > > community at lists.openmoko.org
> > > > http://lists.openmoko.org/mailman/listinfo/community
> > >
> > > --
> > > Carsten Haitzler (The Rasterman)
> > > <raster at openmoko.org>
> >
> >       ______________________________________________
> > Enviado desde Correo Yahoo! La bandeja de entrada más inteligente.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 194 bytes
Desc: This is a digitally signed message part.
Url : http://lists.openmoko.org/pipermail/community/attachments/20080613/c57dc0de/attachment.pgp 