Minor Improvement -- Auto Selection of Sampling Frequency Per Track

[musicfs]

Hi All,

Very few players like rockbox offers the options to select between 44kHz and 48kHz to avoid SRC. Is it possible to make the current manual operation automatic based on the sampling frequency tag in track information?

Best,
Musicfs

[saratoga]

Changing the sampling rate requires stopping playback and then reclocking the DAC.  Can be done quickly on most devices, but it won't be gapless obviously. 

We discussed it a few years ago, but people weren't convinced it was a good idea because of the complexity and because of how efficient resampling is:

http://www.rockbox.org/irc/log-20130706

[Mihail Zenkov]

I read discussion and I think most simple and bug (side effect) free solution will be stop playback if next file have different frequency. Than change frequency and start playback from next file.
Also we should disable crossfade before stop and reenable it after start.

In this case we don't lost sound quality and battery life as it will be with resampling.

[musicfs]

Changing the sampling rate requires stopping playback and then reclocking the DAC.  Can be done quickly on most devices, but it won't be gapless obviously. 

We discussed it a few years ago, but people weren't convinced it was a good idea because of the complexity and because of how efficient resampling is:

http://www.rockbox.org/irc/log-20130706

The sampling rate doesn't change often between tracks in a playlist or an album, so we won't hurt gapless too often as well.

[0rpheu]

I read discussion and I think most simple and bug (side effect) free solution will be stop playback if next file have different frequency. Than change frequency and start playback from next file.
Also we should disable crossfade before stop and reenable it after start.

In this case we don't lost sound quality and battery life as it will be with resampling.

Woudnt  it be easier to verify if the rockbox Sampling freq is the  same as the track each time a new track is played? and if not then ajust it.

[Mihail Zenkov]

Woudnt  it be easier to verify if the rockbox Sampling freq is the  same as the track each time a new track is played? and if not then ajust it.

Yes, but AFAIK to do this correct we should restart (stop, change freq, play next) audio part, as we should flush buffer and recalculate filters (DSP).