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FS#8597 - stuttering & undefined instruction errors on codec-switch with crossfade
Attached to Project:
Rockbox
Opened by Ryan Sawhill (ryran) - Tuesday, 12 February 2008, 01:02 GMT+2
Last edited by Andree Buschmann (Buschel) - Sunday, 30 March 2008, 12:15 GMT+2
Opened by Ryan Sawhill (ryran) - Tuesday, 12 February 2008, 01:02 GMT+2
Last edited by Andree Buschmann (Buschel) - Sunday, 30 March 2008, 12:15 GMT+2
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DetailsTested with an ipod 5g 60GB & r16290.
I described this buggy behavior in Buschel/Soap's PP502x unsupported builds testing thread when I first noticed it. I should've posted the info to the FS entry because it got cleaned up by Soap, but now that Andree's code is in SVN I can post a real bug report. Back then I hadn't yet figured out that mp3/ogg codec switching was the cause. *behavior* With crossfade enabled, there's a stuttering glitchy-ness on track transitions (natural or user-initiated) between mp3 and vorbis (or vorbis & mp3) files. The stuttering is not present when crossfading between mp3 & mp3 or ogg & ogg. Sometimes the stuttering seems to last a bit longer (seconds) than other times. Frequently Rockbox bottoms out with an undefined instruction error (and as of yet, only one time [today] with a data abort error). An important piece of info: the stuttering and the blue-screening doesn't occur when the cpu is boosted--like when the buffer is still being filled or if you manually force the cpu to stay at 80MHz. I first noticed all of this once I started testing Buschel's power-saving patch. It's now in the latest SVN. *to reproduce* Turn on crossfade. Pretty much any setting should work, but the glitches might be more apparent (though the undefined errors will happen eventually no matter what) with longer crossfade times (eg 1 sec fade in, 2 sec fade out delay, 3 sec fade out). Load up an mp3 file and an ogg vorbis file into a playlist. Wait until the hard drive has stopped spinning (so cpu isn't boosted) and then skip forward (or wait for the track to change naturally. There might just be a short skip/dropout in the sound or there might be a stutter/glitchy pop. It'll happen though. If you're really lucky, you'll get an undefined instruction error in your first try. (It's happened to me once. :-) Note: I put PortalPlayer-based for the player type of this bug report. That's just an assumption of course. I haven't tried any other players. |
This task depends upon
Closed by Andree Buschmann (Buschel)
Sunday, 30 March 2008, 12:15 GMT+2
Reason for closing: Fixed
Additional comments about closing: #16889 and #16890
Sunday, 30 March 2008, 12:15 GMT+2
Reason for closing: Fixed
Additional comments about closing: #16889 and #16890
EDIT: fix typo s/task switches/frequency switches/
On track transition _when codec-switching_ as soon as the crossfade begins the cpu locks at 30MHz--it doesn't go back to boosted until the previous track has cleared! Duh. When crossfading between two tracks of the same type, the cpu does the proper, logical thing and stays boosted at 80. A tiny piece of information that anyone who has read all this could've figured for themself but it's key all the same.
PS: My collection consists exclusively of vorbis tracks and mp3s but I took a few minutes to check a few other codecs and .. unsurprisingly it appears to not matter what. In addition to mp3 & ogg, I tested aac, wma, and wav.
1. Have you also experienced during this problem a VERY annoying, high-pitched noise?
2. Does it NEVER occur between mp3 to mp3 transitions?
I have experienced a similar problem as the one you describe, but it also happens during mp3 to mp3 transitions, presenting the high-pitched noise I mentioned. Seems to happen in transitions involving variable bit rate mp3's
2.) Correct. The symptoms described here have never happened to me when crossfading between two tracks of the same format.
FS#8787).FS#8651for an update.