I found a bug Ipod 240 video

[rbhawaii]

Hi This happens with many songs but not all. It is in 3.9.1 and 3.10 (maybe earlier versions too but did not try them)
When I use my self-made WPS and turn on my self-made eq.cfg file which is ...

eq enabled: on
eq precut: 0
eq band 0 cutoff: 60
eq band 1 cutoff: 200
eq band 2 cutoff: 800
eq band 3 cutoff: 4000
eq band 4 cutoff: 12000
eq band 0 q: 7
eq band 1 q: 10
eq band 2 q: 10
eq band 3 q: 10
eq band 4 q: 7
eq band 0 gain: 50
eq band 1 gain: 35
eq band 2 gain: 15
eq band 3 gain: 55
eq band 4 gain: 105

While its on the WPS screen it freezes every 8 seconds for half a second or so.
here is one of the many songs for example...

http://dl.dropbox.com/u/19766273/FreezesEvery8secs.mp3

as you can hear the song on its own never skips and is recorded correctly but the ipod with eq enabled and with the wps makes it skip (and many other songs too)

the interesting thing is when the screen fades out and turns off it no longer skips also if i press the middle button and get off the WPS screen it no longer skips. when i go back to the playing screen it starts to skip again. if i turn all eq settings off it no longer skips.  What do you think? any advice would be greatly appreciated! I really dont want to give up using my WPS i love it to much. Please Help

PS i have deleted .rockbox folder and done a clean reinstall and have tried this on several ipod videos 5.5 - same problem.
attached the wps file

[Buschel]

The skipping seems to be cause by a too high CPU load. The EQ consumes quite some CPU and your custom WPS seems to just pushes the CPU-load over the limit. This is why you do not experience any skipping when the screen goes off or you leave the WPS (no WPS screen updates active anymore).

[rbhawaii]

That really sucks , is there any way for me to fix it?

Did you look at my WPS? I thought it was fairly basic tags with no graphics... ?

It freezes even if nothing is scrolling on the screen. 

Do you think the peak meter is sucking to much cpu and removing it might fix it?

Thanks for your time and help!

[Buschel]

The peak meter is the worst case scenario for an iPod Video WPS (see http://www.rockbox.org/tracker/task/10686). Remove the peak meter and you will be much happier.

Btw, even if there are is no dropout or skipping audible the peak meter and the EQ require lots of CPU-time. As a result you will experience drastically reduced battery runtime.

[rbhawaii]

I see your point, although I have had the peak meter going for years now and have really gotten used to it being there. It's only recently that I decided I want to run the eq all the time and that is when I noticed it makes the music stutter. I guess I could write a config file called "EQ ON.cfg" that will deactivate the peak meter and a "EQ OFF.cfg" that will reactivate it. I just can't believe my WPS is more complex then some really fancy themes with graphics and those dont skip.  Thanks for your advice. If anyone else reading this has any additional input for me I would really appreciate it! 

[Buschel]

The problem with the peakmeter is that it will update the LCD screen lots of times each second. This consumes the CPU (and always did). Other fancy WPS-screens show lots of bitmaps but do not update the screen that often.

[rbhawaii]

Yeah I just looked at the link you sent me it talks about it refreshing 25 times per second. Feels like 10 FPS would work fine too - if thats possible to code in to a future build.

  Close to 2 years ago I discovered they now have 950mah batteries for ipods 5.5 videos. So I bought it thinking it was a Chinese gimmick where they just put a sticker on the 850 battery that says 950 but i was surprised to find out its legit. So i never really had any complaints about the battery life.

In any case you opened my eyes to an interesting fact and I am interested in seeing how much better the ipod will work in none 25FPS mode. I wish this was better documented somewhere for the semi-technical people like me. This and knowing about the "force USB charging " meaning 500ma usb charging would have made my ipod rockbox experience a lot better a lot sooner.

 But in any case i am very grateful to all people involved in rockbox and the contribution that they have made to the mp3 world.

[Buschel]

As a first step I added some recommendations to the manual.

[rbhawaii]

thanks 
Post Merge: December 18, 2011, 08:27:26 AMI removed the peak meter line from my WPS and the EQ works fine with no more stuttering.

It is so disappointing to have to give up the peak meter. 

Do you think trying to tweak the peak meter (in the settings) might help reduce the cpu cycles ? or is it that if its on then its sucking the same amount of extra cpy no matter how its set or what its doing.... do you know?

[Buschel]

If you can compile rockbox you might just check the latest patch in http://www.rockbox.org/tracker/task/10686. In case you cannot build rockbox I have uploaded a custom build that includes this patch -> http://www.sendspace.com/file/60hnou

The patch reduces the update to 10 fps and should significantly reduce the CPU load caused by the peak meter.

[rbhawaii]

Hi Buschel
Thanks for compiling it for me because I do not know how to do it myself.

I installed it and it still stutters same as before except this time its every 4 seconds.

The other weird thing was when I paused it and then resumed it the screen kept saying paused even though the song was now playing.

So once you pause it the screen keeps thinking it paused (untill reboot) even though its not. weird.

 I am glad to try anything you come up with , I have now written another wps where i either have the peak meter or the eq on but not both at the same time it seems to work just fine with 3.10.

The RockBox EQ feature on the ipod is worth its weight in gold, even though it has no weight LOL it really is valuable for anyone who appreciates quality sound. Thanks again for your attention to all of this!

[Buschel]

The custom build results in *more* stuttering? Can you test against a current svn build (e.g. r31360)?

[rbhawaii]

hi
yes the one you sent me resulted in more stuttering. i just installed r31371-111219

it skips at (seconds) 5,12,18,24,30,37,43,49 etc...

it also has the weird pause glitch- once paused the screen says paused but when unpaused the song plays but the screen does not stop saying paused.

i am using the above song from my dropbox in all of these tests