winamp's 2.8x out_ds plugin quality fix
a few of you may have read my other post a day or so back ( http://www.mp3car.com/vbulletin/show...threadid=10570 ) where I rambled on about some crap.... and then reported on a few fixes I made by upgrading to latest winamp/etc and getting better sound qual with the out_ds plugin... well i did a bit more investigation and thought I would share my discovery....
after looking at Peter Blops website (the creator of the out_ds plugin) i stumbled onto his forum at winamp.com ( http://forums.winamp.com/forumdispla...s=&forumid=129 ) and found this interesting bit of text in the out_ds FAQ....
Q: I get really bad sound quality with my <insert ISA soundcard name here>.
A: Short explaination: compatibility tab, "create primary buffer".
Long explaination: DirectSound tends to perform argessive downsampling to save ISA bandwidth when using old ISA soundcards. Enabling "Create primary buffer" will force sound format played by hardware to be the same as format of played stream. This affects only really old devices.
so basically what I 'thought' was poor sound/worse than previous - in my system since upgrading to my TFT (which was the same time I ditched the SQRsoft crossfader for the free out_ds plugin) I was very much correct....... I had been getting downsampled 22kHz mp3s! argh!!!!!! I knew something was a miss, but I dont always trust my ears!! :)
Q: Are there any differences in audio quality between DirectSound and waveOut ?
2. In win9x OS line, DirectSound does low-level hw access on its own, meaning that it may behave differently than waveOut in many cases, eg. well-documented downsample-to-22khz-on-ISA-card syndrome (quick painless fix: "create primary buffer" option, enabled by default on all win9x anyway).
so as the quotes above expain, directsound will automatically downsample to 22khz to save ISA bandwidth (in the case your sound card is ISA).... now I have a PCI SB128, but I am sure that I have read that these cards are infact ISA in 'PCI clothing'... but as Peter explains, ticking the 'create primary buffer' will force/bypass the downsample process.....
well I thought it was interesting, and I am sure that at least one other mp3'er out there will be in the same situation (and maybe dont even realise the downsamping is happening) since winamp 2.8x is the player of choice (rightfully so!) and a good old ISA/PCI sound card is often the hardware of choice for a car system......
hope it can help someone, and at least I thought it was an interesting read... ;)