Thanks to Aurelien Jacobs for the new FFmpeg VOC subsystem. I want to express my particular gratitude that he did everything right in the process:
- submitted the module to the project along with the correct updated documentation
- created a MultimediaWiki page for the format
- provided an impressive variety of samples
For the uninitiated, the VOC format was a.k.a. the Creative Voice file format which was tied to specific multimedia hardware, as was the case with so many old multimedia formats. This format was tied to the original line of Creative Labs’ Sound Blaster audio cards, so much so that the format actually stored the Sound Blaster DAC frequency divisor for PCM data. VOC files originally stored PCM or any of the custom ADPCM formats that SB hardware apparently supported, including a 2.6-bit format. Details of these custom formats are unknown.
“Details of these custom formats are unknown.” Actually, they’re known! Download the source code for DOSBOX and you’ll see code that decompresses the ADPCM formats.
Hehe, just wanted to post the exactly same thing :)
But does someone have sample VOCs with 2- and 2.6-bit ADPCM compression?
Great, great, great :-)
So expect to see those ADPCM formats supported in ffmpeg soon, with some samples ;-)
I uploaded samples to Mike about 18-20 months ago… Mike, were those samples erased?
Someone probably has them somewhere. Do you remember the filenames?
I’ve just sent those samples to Mike.
Thanks for them Jim, they were really useful :-)
Also note, that the ADPCM implementation in DOSBOX is pretty broken and not much useful (but still gave me some ideas).
Those ADPCM/VOC samples have been posted here:
http://multimedia.cx/samples/voc/voc_adpcm_samples/