[MPlayer-users] MPlayer Audio Quality

[Mark Williams (MWP)]

> On Wed, May 18, 2005 at 02:09:16AM +0930, Mark Williams (MWP) wrote:
> > Greetings all,
> > 
> > Due to all the different audio media formats i play, and requiring the use of
> > JACK, i use mplayer for all my music playing duties.
> > 
> > Im wondering how pure the audio out of mplayer is though.
> > 
> > For example, if i use the FLAC decoder to play music, mplayer shows it goes
> > through a lot of format conversions and i assume, a couple of volume filters before it
> > reaches JACK.
> > 
> > I assume its going through a few volume filtes as using +,- keys changes volume
> > separtley to the command line volume option.
> > 
> > Can anyone explain the audio chain inside mplayer and how best to optimise it
> > for quality?
> > 
> > I also just made and tried playing a simple 48khz, 32bit WAV file.
> > I get this:
> > 
> > Playing test.wav.
> > Audio file detected.
> > ==========================================================================
> > Forced audio codec: mad
> > Opening audio decoder: [pcm] Uncompressed PCM audio decoder
> > AUDIO: 48000 Hz, 2 ch, floatle, 3072.0 kbit/100.00% (ratio: 384000->384000)
> > Selected audio codec: [pcm] afm:pcm (Uncompressed PCM)
> > ==========================================================================
> > Checking audio filter chain for 48000Hz/2ch/floatle -> 48000Hz/2ch/floatle...
> > AF_pre: 48000Hz/2ch/floatle
> > AO: [Jack] Initialising library.
> > AO: [Jack] Sample rate mismatch, trying to resample.
> > AO: [Jack] OK. I'm ready to go (44100 Hz/2 channels/16 bit)
> > AO: [jack] 44100Hz 2ch s16le (2 bps)
> > Building audio filter chain for 48000Hz/2ch/floatle -> 44100Hz/2ch/s16le...
> > 
> > Why is the audio being output to JACK at s16le when JACK can handle 32bit audio?
> 
> MPlayer doesn't do 32bit audio, and apparently your device doesn't
> support 48000 Hz sampling so it gets resampled to 44100 too. Neither
> of these changes is audible unless the volume of your file is
> EXTREMELY low and being heavily boosted by the amp after it comes out
> of the soundcard.

Thanks for the reply, but it doesnt really answer my questions.
First, the conversion to 44100 was expected, as this is what i am running JACK at.
Secondly, from what i have read in the mplayer man page, it can handle 32bit audio.

Can anyone else who is very familiar with MPlayers audio handling chain and JACK output
help me?

Is it possible to get bit perfect audio out of MPlayer?

Thanks again.