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| Audio codec
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dvik
msx master
Berichten: 1312 |  Geplaatst: 30 Oktober 2007, 05:54 |
Prodatron, do you have support for PCM or ADPCM in Symamp? If we manage to get one of the better SCC replayers to work without noise it would be nice to include in Symbos. We still have some work before the quality is good enough for SymbOS though.
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Prodatron
msx master
Berichten: 1109 | Geplaatst: 30 Oktober 2007, 11:47 |
No, it's not yet supported. But how much CPU power is required to play a PCM (or even ADPCM)?
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ARTRAG
msx master
Berichten: 1681 | Geplaatst: 30 Oktober 2007, 12:41 |
It depends, ATM the most promising solution needs only to be called once per interrupts and asks for about the 4% of the CPU time,
the problem is that the SCC seems not allow any change (or even access for reading) to its wavetable while playing samples
without adding noise  
The solution that works without noise and troubles (the one in the dvick's demo) needs external synchronization for updating the samples (e.g. the Hblank or cycle accurate code), in this case the application becomes really time critical and hardly can be implemented in a NON real time OS like Symbos (the player has strict limits in the time windows where it can be called)
Investigations are ongoing... |
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NYYRIKKI
msx master
Berichten: 1509 | Geplaatst: 30 Oktober 2007, 14:00 |
AFAIK SymbOS does not currently support custom interrupts, so currently phasedifference solution is only one that could work...
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dvik
msx master
Berichten: 1312 | Geplaatst: 30 Oktober 2007, 16:55 |
I think that one is the best choise for symbos too. Not sure how much CPU is needed for loading the samples from a HD but I imagine it won't be too much, so it will be possible to play music in the background while doing other tasks in SymbOS.
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Alex
msx lover
Berichten: 96 | Geplaatst: 30 Oktober 2007, 23:51 |
Quote:
| That would be great Alex. Btw, do you have the format description of the MSX Audio ADPCM?
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I just remembered that I put the assembly sources long time ago on funet. So nowadays, they can be found on the msxarchive site. It concerns file xadpcm.pma
You will need to extract with pmext.
The format is described in the MSX Audio manual, from the website of Hans Otten
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Alex
msx lover
Berichten: 96 | Geplaatst: 31 Oktober 2007, 00:27 |
I just dowloaded xadpcm.pma from msxarchive site, transferred it to my MSX and tried to extract it with pmext. I got an 'overseek' error message. Anybody experiencing the same problem?
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AuroraMSX
msx master
Berichten: 1248 | Geplaatst: 04 November 2007, 16:26 |
Quote:
| I just dowloaded xadpcm.pma from msxarchive site, transferred it to my MSX and tried to extract it with pmext. I got an 'overseek' error message. Anybody experiencing the same problem?
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I downloaded the PMA, extracted it with lha on my linux box without problems. Here is the package in a somewhat more modern zip format...
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manuel
msx guru
Berichten: 3447 | Geplaatst: 04 November 2007, 18:44 |
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