Best quality resampling method?
Reply #12 – 2009-05-29 19:18:53
I have found this page (wich have most of this methods listed), but still not sure what will the best for movies (48 kHz, AC3 artefacts). Are your preferences solely based on the specs (graphs) or was there also listening involved ? Hi, I'm new to this great hydrogen forum but i have some experience with music resampling and would like to contribute. For me the use of resampling is to change the speed of an audio file or upsampling the music so that it sounds more natural. I dont know much about PAL / NTSC speed change or tempo correction but i have "upsampled" my music since i got my first "real" sound card. It was a creative audigy soundcard that had a real problem, back then it was unknown that it could play only in 48000Hz, 96000Hz and 192000Hz without sounding crappy. Somehow i witnessed that, music playing upsampled to 48000Hz sounded much more natural and pleasant on it. From this day on i have always resampled my music one way or the other and tested all mentioned resamplers. I think there's no better resampler than Sox (rate -v 48000Hz). In comparison the bass and highs are more musical sounding with a good resampler. The command one-liner for resampling with Sox (in highest possible quality!), so that an 48000Hz file becomes 4% longer, would be : Sox.exe YourFile.wav --buffer 16384 -f -b 64 -c 1 -t raw -f -b 64 -c 2 - | Sox.exe -t raw -r 48k -f -b 64 -c 2 - --buffer 16384 -t raw -f -b 64 -c 2 - rate -p 18 -v 50002 | sox.exe --buffer 16384 -t raw -r 48k -f -b 64 -c 2 - -s -b 32 High_Slower_Resampled_Stereo.wav Pretty easy, eh? Info: 48000 + 4,17% = 50002 you can change it in the middlepart (-v 50002) If you want to try it, download my AC3 speedchange. Drag'n'Drop a .wav file on the Slower! Faster! files and the music is resampled by Sox +-4,17% , the resulting file is 32-bit (-s -b 32). Performance is okay, 1 minute of music in 9 seconds. See How-to in the download for full instructions on demuxing and decoding the AC3 stream in 32bit floating point.http://sp-bausysteme.eu/ac3-speedchange.zip Maybe i make a full featured gui for this programm. Please tell me what you think about it.