File-based audio playback - compressed vs. uncompressed

[Welder]

My boss used to complain that our monthly sales figures were terrible. I stopped using Zip to send him the Excel spreadsheet, and there was an immediate night and day difference in the quality of our figures! Quite remarkable.

Yep Bob, a bit of both.

Thing is, if some bloke down the pub keeps banging on about how he can do 100mph on his bicycle after everyone has sat around nodding and patting him on the head and saying "yes mate" some arshole like me comes along and says "I think yer full of shit. Get yer bike and lets see you do it".

I realise here on AoS its not accepted practice but that unfortunately doesn't prevent my natural inclination towards aresholism.

[bobbasrah]

My boss used to complain that our monthly sales figures were terrible. I stopped using Zip to send him the Excel spreadsheet, and there was an immediate night and day difference in the quality of our figures! Quite remarkable.

Well known.....it buggered up the macro in the economics.....
Once had a boss who up until 2000 when I left, used excel for all his letters so he knew how many lines there were..... Strange people abound....

[bobbasrah]

Yep Bob, a bit of both.

Thing is, if some bloke down the pub keeps banging on about how he can do 100mph on his bicycle after everyone has sat around nodding and patting him on the head and saying "yes mate" some arshole like me comes along and says "I think yer full of shit. Get yer bike and lets see you do it".

I realise here on AoS its not accepted practice but that unfortunately doesn't prevent my natural inclination towards aresholism.

Is there not an old joke about that where a guy on a bike kept overtaking a guy's car at increasingly high speed, until his braces snapped off the door handle.....

[AlexM]

Even the Touch buffers though.

Yes, I get about 30 seconds of playback buffering when I disconnect the network cable. It doesn't buffer the output though AFAIK.

Cheers,
A.

[bobbasrah]

It's funny that you mention this. I have long held the believe that differences in the atmospheric pressure can have an effect on the sound reproduced by a set of speakers. I also think that water droplets in the air can affect the sound at various frequencies. This is not as far fetched as it sounds, considering the speed of sound in water is different to the speed of sound in free air.

After 4 hours, still nothing from Stan to further the debate since the above, despite our willingness in trying to get to the bottom of the puzzle that was raised by him.......

[dave2010]

Since the decoding takes place in your computer, have you considered that to be the source of the problem?

Possibilities:

1. Poor decoding - software errors. Not a FLAC issue, but a player issue.

2. Decoding good, but takes time. If done on computer side this could lead to timing errors, or errors due to improper buffering.

3. Some hardware players, such as the Logitech Touch do FLAC decoding. As 1 - maybe there are errors.

4. Some players, such as the Logitech Touch do FLAC decoding. As 2 maybe timing delays affect the output.

5. Corruption in the communication stream might make a mess of things!

Seems a bit unlikely, but nevertheless corruption in a compressed data stream may cause more errors than corruption in an uncompresssed stream.

[AlexM]

After 4 hours, still nothing from Stan to further the debate since the above, despite our willingness in trying to get to the bottom of the puzzle that was raised by him.......

I have discounted Stan's hypothesis - isn't a problem with loss of data through compression/decompression. I'd welcome any further input from him though, if he has one.

Dave,

Some interesting thoughts.

1) most people use the open source libFLAC libraries - these seem to work correctly as proved.
2) Possible, I suppose. I guess the flac is decoded to LPCM data before playout starts, or is it? Do we know if PC audio players put the flac decoder in the audio pipeline, and decode FLACs frame by frame?. If so this could cause software-induced jitter on the output, but again buffering on the DAC should sort it out.
3) As 1)
4) As 2)!
5) Don't know about this.

Cheers,
Alex

[Clive]

I guess the flac is decoded to LPCM data before playout starts, or is it? Do we know if PC audio players put the flac decoder in the audio pipeline, and decode FLACs frame by frame?

For players like Foobar, Jriver etc I believe you'll find it's frame by frame.

For JPLAY it all done before playback starts.

[AlexM]

For players like Foobar, Jriver etc I believe you'll find it's frame by frame.

For JPLAY it all done before playback starts.

Clive,

Thanks - that's useful.

If software-induced jitter is a possible explanation, then predecoding of FLAC before playback should eliminate the effect of this. Anyone compared FLAC to WAV playback using JPLAY?.

Alex

[Clive]

Clive,

Thanks - that's useful.

If software-induced jitter is a possible explanation, then predecoding of FLAC before playback should eliminate the effect of this. Anyone compared FLAC to WAV playback using JPLAY?.

Alex

I listened for it but can't hear a difference. The developers of JPLAY claim they can hear a difference and therefore always use WAV. Sorry, that's not much help!

If there is a difference maybe it's in an area that only some of us are sensitive to?