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Tremor issues.
HbG
post May 6 2005, 12:23
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I first noticed this some 2 years ago. I've got a HP Jornada 568 PocketPC with a 256MB CF card which i use as MP3/OGG/MPC player, i know this is hardly the best way to listen to music, but it's better to use the hardware i have than shell out for something new.

The problem is, i hear noticeable artifacts when playing OGG's with certain types of music, most notably continous low tones. A good example where this happens is the start of Radiohead - Lucky. It sounds like there is some weird higher harmonic in it, i can't really describe it, but it's very audible to me.

Mac explained to me this is what you can hear when you reduce bit depth without dithering. Since PocketPC's as far as i'm aware don't have any floating point units and therefore can't use the normal Vorbis decoder, it would appear this is a bug in Tremor. I've tried two different programs to play OGG's on the PocketPC, PocketDiVX (later renamed to PocketMVP) and BetaPlayer, it makes no difference.

Because the issue might also be something other than Tremor and i can't decode to a wav file on my PocketPC, i have no way of verifying this and putting some samples online for everone to listen to. Is there a Tremor compile for windows i can use to confirm this?


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Veni Vidi Vorbis.
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john33
post May 6 2005, 13:48
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I think I'm right in saying that there has never been a formal release of Tremor. The library code was, IIRC, intended to be little more than a 'starting point' for the creation of environment specific implementations. I seem to recall having to tweak it slightly to get it to fly in the win32 environment; an environment that is hardly its intended target!!

I believe there have been few, if any, changes to the reference libs since initial availability.

None of this really answers your questions, but sets a little background, hopefully!!


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John
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aspifox
post May 6 2005, 16:16
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QUOTE (john33 @ May 6 2005, 12:48 PM)
I think I'm right in saying that there has never been a formal release of Tremor. The library code was, IIRC, intended to be little more than a 'starting point' for the creation of environment specific implementations. I seem to recall having to tweak it slightly to get it to fly in the win32 environment; an environment that is hardly its intended target!!

I believe there have been few, if any, changes to the reference libs since initial availability.

None of this really answers your questions, but sets a little background, hopefully!!
*


If anything, Tremor has seen quite a lot more development than the 'standard' Vorbis decoding code, including IIRC the first implementation of a libogg2-style demuxer with zero-copy. The development, however, has mostly been tucked away on a side-branch of CVS, and, as you say, doesn't see formal releases.

As a side-point to the side-point, Tremor is actually very easy to build almost anywhere; I'm shipping win32 and Linux/x86 software using Tremor as the preferred decoder, for footprint reasons. Back on topic somewhat, Tremor in low-precision mode often demonstrates an unpleasant sort of mechanical buzzing edge to the output, but normal-precision Tremor was 'good enough' for me. I hope no-one is shipping player products using low-precision Tremor mode, but...
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picard
post May 23 2005, 08:32
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QUOTE (aspifox @ May 6 2005, 04:16 PM)
I hope no-one is shipping player products using low-precision Tremor mode, but...
*

Both PocketMVP and BetaPlayer uses low-precision mode smile.gif Using EVC (no ARM inlines) the none low-precition mode is much slower and these two player are mainly focus on video playback so speed does make a big difference. Later I will try to use GCC for tremor compiling...
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rt87
post May 23 2005, 17:59
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QUOTE (picard @ May 23 2005, 03:32 PM)
QUOTE (aspifox @ May 6 2005, 04:16 PM)
I hope no-one is shipping player products using low-precision Tremor mode, but...
*

Both PocketMVP and BetaPlayer uses low-precision mode smile.gif Using EVC (no ARM inlines) the none low-precition mode is much slower and these two player are mainly focus on video playback so speed does make a big difference. Later I will try to use GCC for tremor compiling...
*


You missed a good player for PocketPC wink.gif
It is GSPlayer. It supports mp3/ogg and plugins.
http://hp.vector.co.jp/authors/VA032810/


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Sorry for my English.
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picard
post May 23 2005, 22:23
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QUOTE (rt87 @ May 23 2005, 05:59 PM)
You missed a good player for PocketPC wink.gif
*

I was just stating which players use low-precision for sure.
Btw there is another good open-source audio player for PocketPC called MortPlayer...
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system_saboteur_...
post Jul 1 2005, 13:13
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Hi all,
I'm searching for a new algorithm for mdct_backward function of Tremor lowmem and I found that Johannes Sandvall, Erik Montnemery implemented it before (http://lists.xiph.org/pipermail/tremor/2003-November/000905.html).
The lowmem tremor with a new mdct backward function was available. I goto the link: http://www.sandvall.nu/patch but this link was dead sad.gif .

Could someone please send me this patch?

Thanks in advance wink.gif
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Posts in this topic
- HbG   Tremor issues.   May 6 2005, 12:23
- - john33   http://www.rarewares.org/files/ogg/oggdecT.zip   May 6 2005, 12:33
|- - HbG   Thanks for the link. Seems the issue is with the ...   May 6 2005, 13:24
- - john33   I think I'm right in saying that there has nev...   May 6 2005, 13:48
|- - aspifox   QUOTE (john33 @ May 6 2005, 12:48 PM)I think ...   May 6 2005, 16:16
|- - HbG   Low precision mode you say.. that might be it. A q...   May 6 2005, 21:32
|- - picard   QUOTE (aspifox @ May 6 2005, 04:16 PM)I hope ...   May 23 2005, 08:32
||- - rt87   QUOTE (picard @ May 23 2005, 03:32 PM)QUOTE (...   May 23 2005, 17:59
||- - picard   QUOTE (rt87 @ May 23 2005, 05:59 PM)You misse...   May 23 2005, 22:23
||- - system_saboteur_13   Hi all, I'm searching for a new algorithm for ...   Jul 1 2005, 13:13
||- - timber   QUOTE (system_saboteur_13 @ Jul 1 2005, 13...   Jun 3 2009, 14:14
|- - cruzlee   QUOTE (aspifox @ May 6 2005, 16:16) I hop...   Aug 14 2008, 21:57
- - HbG   Even if it doesn't answer my question, it stil...   May 6 2005, 14:43
- - HbG   It'd be nice if it were possible to use normal...   May 23 2005, 12:50
- - Mike Giacomelli   It would be odd for them to use low precision give...   Aug 14 2008, 22:27
- - Yirkha   Unfortunately, Tremor in latest iAUDIO 7 firmware ...   Aug 15 2008, 14:37
|- - sprockkets   Is by inferring or by actually seeing the code? At...   Aug 15 2008, 20:45
- - Yirkha   By actually seeing the co... uhm, nobody can have ...   Aug 15 2008, 21:44
- - Rotareneg   I'm not sure iAudio themselves even touch that...   Aug 15 2008, 21:52
- - sprockkets   I see. The D2, U3, and 7 use the same ARM946-ES co...   Aug 20 2008, 01:20
- - sprockkets   Well, I tried, but of course the firmware is signe...   Aug 20 2008, 01:51
|- - Mike Giacomelli   QUOTE (sprockkets @ Aug 19 2008, 20:51) W...   Aug 20 2008, 04:22
- - sprockkets   Ok, so explain to me what it means to ((((n)>...   Aug 20 2008, 04:37
|- - Mike Giacomelli   QUOTE (sprockkets @ Aug 19 2008, 23:37) O...   Aug 20 2008, 04:45
- - Yirkha   As have been already stated by others, it's no...   Aug 20 2008, 05:15
- - sprockkets   I see. And just by changing the value did not work...   Aug 20 2008, 06:00
- - Yirkha   I'm hacking the original firmware, selfishly w...   Aug 20 2008, 17:30
- - pellgarlic   i know this is a relatively old post, but i came a...   May 29 2009, 15:33
- - Yirkha   That's great news, thank you very much! It...   May 29 2009, 18:14
- - AshenTech   ogg support isnt really that hard to find, sansa c...   Jun 1 2009, 01:40
- - Mike Giacomelli   Hopefully MPC will be available on the Fuze soon v...   Jun 1 2009, 03:15
|- - AshenTech   QUOTE (Mike Giacomelli @ May 31 2009, 20...   Jun 1 2009, 05:12
|- - Mike Giacomelli   QUOTE (AshenTech @ Jun 1 2009, 00:12) onl...   Jun 1 2009, 15:55
|- - AshenTech   QUOTE (Mike Giacomelli @ Jun 1 2009, 08:5...   Jun 2 2009, 03:39
|- - Mike Giacomelli   QUOTE (AshenTech @ Jun 1 2009, 22:39) QUO...   Jun 2 2009, 03:46
|- - Soap   QUOTE (AshenTech @ Jun 1 2009, 22:39) QUO...   Jun 2 2009, 03:50
- - Rotareneg   Wow, I figured they would never fix that! Time...   Jun 1 2009, 18:07


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