On Mon, 22 Oct 2001, David Burrows wrote: > My question is this. How would one go about modifying say mpg123, so that > it uses 3x256 (or 3x128) byte buffering? I've ran the source through > doxygen, and started to have a brief look into it but I am wondering if > someone has already achieved this or could give a description of where to > start.
You can download the archive located at http://www.alsaplayer.org, unpack and then check the output/oss/oss.c file, specifically the set_buffer routine. Similar code should be present in the mpg123 source tree. > The bonus question is about pitch control. I understand that this can be > achieved by simply changing the sampling rate, however, I'm wondering if > anyone has knowledge of fast or high quality resampling algorithms? You can change the hardware sampling rate of your audiocard to get pitch (speed) control. As a bonus alsaplayer also allows pitch (speed) control, but this is quite specific (code is contained in a C++ class), and it doesn't change the hardware sampling rate. It also does negative speed control (i.e. play an mp3/ogg in reverse), but it uses the crudest algorithm (bresenham) which is simply duplicating/removing frame values as necessary, it doesn't even interpolate. > Any thoughts, urls, patches or otherwise on the subject would be great. =) That's all I have from my side :) Good luck, Andy -- AlsaPlayer, http://www.alsaplayer.org/
