Josh Coalson <xflac@yahoo.com> wrote:> --- Eric Wong <eric@petta-tech.com> wrote: > > Just to let you guys know, I've been listening to FLAC (compression > > level 2 or lower) tunes on my 3rd generation ipod running ipodlinux > > (modified uCLinux) for the past few days. No skips or slow-downs > > whatsoever using MPD to play music. > > how loaded is the cpu with a -2 FLAC file? also, how does the > battery life compare against regular ipod use? not sure how > much would be due to FLAC vs. MP3/AAC and how much due to > ipodlinux vs. native ipod OS.Not sure about CPU load, but I suspect not a whole lot. I have -8 playing comfortably (slows down a little during UI (what little UI I have) interaction if it's reading from disk at the same time). I haven't been able to get plain-old telnet to it working the past week or so, but I can telnet into MPD. I optimized a few functions a little in libFLAC and MPD in C and it was enough for now. I'll post those to the -dev mailing list in a bit, but I haven't been able to get very far with ARM asm (though reading it has given me great insight on how to optimize my C). Battery life: >= 2 hours, that's the longest I've left it unplugged and playing. No idea compared to the Apple software, I've only used the Apple software it for a few minutes to make sure the hardware was working right when I got it. I'll run a test this weekend and see how long it takes to drain. ipodlinux is only using one of the ARM cores, and afaik, not all of the processor cache. David Carne (another ipodlinux dev) has gotten the second core to execute arbitrary instructions but syscalls don't work yet. True SMP also seems out of the picture, as the cache is "broken" (I'm not that knowledgeable enough in this area and will let someone else explain it). A cursory search of libFLAC tells me that I can at least run the CPU-critical functions in COP without using syscalls. A calloc/malloc or two exists, but I can get rid of those, I think. Afaik, MP3s (<=128kbps) play fine using the Intel Processor Primitives (IPP), but I don't think I can't use it with MPD (which is GPL). libMAD isn't playing at full speed, but does play under ipodlinux with MPD, but I haven't really pursued it. Tremor support hasn't been added to MPD yet, but shouldn't take long for anyone to do it since MPD is pretty modular and I don't have that much time... optimizing is a different problem. MPD also supports AAC through libFAAD, but I've never tried that even on a desktop machine. Lossy formats don't interest me a whole lot, so I'm tempted to leave supporting those to other devs. -- Eric Wong -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: Digital signature Url : http://lists.xiph.org/pipermail/flac/attachments/20050202/5a8df0b1/attachment.pgp
--- Eric Wong <eric@petta-tech.com> wrote:> Josh Coalson <xflac@yahoo.com> wrote: > > --- Eric Wong <eric@petta-tech.com> wrote: > > > Just to let you guys know, I've been listening to FLAC > (compression > > > level 2 or lower) tunes on my 3rd generation ipod running > ipodlinux > > > (modified uCLinux) for the past few days. No skips or slow-downs > > > whatsoever using MPD to play music. > > > > how loaded is the cpu with a -2 FLAC file? also, how does the > > battery life compare against regular ipod use? not sure how > > much would be due to FLAC vs. MP3/AAC and how much due to > > ipodlinux vs. native ipod OS. > > Not sure about CPU load, but I suspect not a whole lot. I have -8 > playing comfortably (slows down a little during UI (what little UI I > have) interaction if it's reading from disk at the same time). I > haven't been able to get plain-old telnet to it working the past week > or > so, but I can telnet into MPD. I optimized a few functions a little > in > libFLAC and MPD in C and it was enough for now. I'll post those to > the > -dev mailing list in a bit, but I haven't been able to get very far > with > ARM asm (though reading it has given me great insight on how to > optimize > my C).excellent. FLAC 1.1.2 should be out this week. the focus for FLAC 1.1.3 will be apple: PPC optimizations and quicktime/itunes. your/Chris's/Miroslav's patches are making a big difference.> A cursory search of libFLAC tells me that I can at least run the > CPU-critical functions in COP without using syscalls. A > calloc/malloc or two exists, but I can get rid of those, I think.OK, I'll keep this in mind for the future. I am working on an interface for single frame encoding/decoding that will remove the need for callbacks and let the client do all the memory management. this may improve the speed too as there will be less buffer copying. if this can help I can add it to the FLAC 1.1.3 items. Josh __________________________________ Do you Yahoo!? All your favorites on one personal page – Try My Yahoo! http://my.yahoo.com
Eric Wong <eric@petta-tech.com> wrote:> Josh Coalson <xflac@yahoo.com> wrote: > > --- Eric Wong <eric@petta-tech.com> wrote: > > > Just to let you guys know, I've been listening to FLAC (compression > > > level 2 or lower) tunes on my 3rd generation ipod running ipodlinux > > > (modified uCLinux) for the past few days. No skips or slow-downs > > > whatsoever using MPD to play music. > > > > how loaded is the cpu with a -2 FLAC file? also, how does the > > battery life compare against regular ipod use? not sure how > > much would be due to FLAC vs. MP3/AAC and how much due to > > ipodlinux vs. native ipod OS. > > Not sure about CPU load, but I suspect not a whole lot. I have -8 > playing comfortably (slows down a little during UI (what little UI I > have) interaction if it's reading from disk at the same time). I > haven't been able to get plain-old telnet to it working the past week or > so, but I can telnet into MPD. I optimized a few functions a little in > libFLAC and MPD in C and it was enough for now. I'll post those to the > -dev mailing list in a bit, but I haven't been able to get very far with > ARM asm (though reading it has given me great insight on how to optimize > my C). > > Battery life: >= 2 hours, that's the longest I've left it unplugged and > playing. No idea compared to the Apple software, I've only used the > Apple software it for a few minutes to make sure the hardware was > working right when I got it. I'll run a test this weekend and see how > long it takes to drain.I guess my battery is dying. I only seem to get 2 hours +/- 15 minutes. I only get that much in disk mode or idle, too. I've never had power management on my ipod, so it was probably plugged in and at full charge for too long. -- Eric Wong -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: Digital signature Url : http://lists.xiph.org/pipermail/flac/attachments/20050210/33b25847/attachment.pgp
Eric Wong wrote:>Eric Wong <eric@petta-tech.com> wrote: > > >>Josh Coalson <xflac@yahoo.com> wrote: >> >> >>>--- Eric Wong <eric@petta-tech.com> wrote: >>> >>> >>>>Just to let you guys know, I've been listening to FLAC (compression >>>>level 2 or lower) tunes on my 3rd generation ipod running ipodlinux >>>>(modified uCLinux) for the past few days. No skips or slow-downs >>>>whatsoever using MPD to play music. >>>> >>>> >>>how loaded is the cpu with a -2 FLAC file? also, how does the >>>battery life compare against regular ipod use? not sure how >>>much would be due to FLAC vs. MP3/AAC and how much due to >>>ipodlinux vs. native ipod OS. >>> >>> >>Not sure about CPU load, but I suspect not a whole lot. I have -8 >>playing comfortably (slows down a little during UI (what little UI I >>have) interaction if it's reading from disk at the same time). I >>haven't been able to get plain-old telnet to it working the past week or >>so, but I can telnet into MPD. I optimized a few functions a little in >>libFLAC and MPD in C and it was enough for now. I'll post those to the >>-dev mailing list in a bit, but I haven't been able to get very far with >>ARM asm (though reading it has given me great insight on how to optimize >>my C). >> >>Battery life: >= 2 hours, that's the longest I've left it unplugged and >>playing. No idea compared to the Apple software, I've only used the >>Apple software it for a few minutes to make sure the hardware was >>working right when I got it. I'll run a test this weekend and see how >>long it takes to drain. >> >> > >I guess my battery is dying. I only seem to get 2 hours +/- 15 minutes. >I only get that much in disk mode or idle, too. I've never had power >management on my ipod, so it was probably plugged in and at full charge >for too long. > > > >------------------------------------------------------------------------ > >_______________________________________________ >Flac mailing list >Flac@xiph.org >http://lists.xiph.org/mailman/listinfo/flac > >Well, Flac is more bandwidth intensive then mp3/ogg/etc... and from what i read about linux on ipod this means that the hard disk is on constantly (with the apple firmware the songs are held in ram and the HD is off most of the time) which drains your batteries faster. As such you will find that your batteries are probably wearing out faster due to increased usage (faster discharging and charging) + the lackof power management is an issue as well, as flac is less CPU intensive potential power savings could be had as soon as they get it working (fully) just speculating...