Transcoding Questions

[qmanblue]

Sorry for the newb nature of this question, but here goes.

I have just set up my Win2k server with the Fireflymedia server to serve my new Roku M1001. (Very impressive software, nice job gang!)

At first it wouldn’t play my WMAL format files (file type not supported). After an upgrade to WinMedia Player 9 & to a newer version of Fire Fly it started working (presumably because the trans coding now works).

My plan was to get it working on my old server before I upgrade to a new Linux OpenSUSE 10.2 box. It appears that people have gotten trans coding to work there, so that’s step 2.

My questions:
What exactly does transcoding do in terms of impacting the audio quality of the file playback (my M1001 dumps its digital signal right to my Stereos digital decoder through the optic connection)?

I went with WMAL originally for audio quality, is there another lossless format I should consider that would be better with firefly & the sound bridge (especially when I move to Linux?)

Thanks for your help.

[S80_UK]

@qmanblue wrote:

My questions:
What exactly does transcoding do in terms of impacting the audio quality of the file playback (my M1001 dumps its digital signal right to my Stereos digital decoder through the optic connection)?

I went with WMAL originally for audio quality, is there another lossless format I should consider that would be better with firefly & the sound bridge (especially when I move to Linux?)

Hi,

Simple question – simple answer. If the SoundBridge volume is set to 100%, then the digits out from the SPDIF to your amplifier are identical to the digits before encoding to a lossless format. Same goes for FLAC and other lossless formats. BTW, FLAC is also pretty well supported in the Linux world.

Cheers,

Les.

[Anonymous]

@qmanblue wrote:

I went with WMAL originally for audio quality, is there another lossless format I should consider that would be better with firefly & the sound bridge (especially when I move to Linux?)

I chose FLAC because of it’s wide acceptance and open standard. However, if you choose apple lossless, you wouldn’t have to transcode at all as the Soundbridge supports apple lossless. I keep hoping that Roku will be supporting native FLAC soon.

[fizze]

@S80_UK wrote:

If the SoundBridge volume is set to 100%, then the digits out from the SPDIF to your amplifier are identical to the digits before encoding to a lossless format.

To be incredibly verbosive, this is true for the M1000 and M2000, but its false for the M1001 models.
The M1001 resamples all its data to 48kHz sampling rate. Also for the digital outputs. So the SNR deteriorates, and so does the total harmonic distortion.

For most people this is inaudible, and most equipment isnt good enough to even notice the difference. IT is there though. Audiophiles can hear the difference.

Sadly enough, this is also a reason why AC3 or DTS encoded material cnnot be passed through a M1001 model anymore.

[qmanblue]

How do you tell the difference? My package said M1000, but my unit has the rear connections so I assumed M1001.

Also, why the difference? Different processing chip?

[jtbse]

@qmanblue wrote:

How do you tell the difference? My package said M1000, but my unit has the rear connections so I assumed M1001.

Also, why the difference? Different processing chip?

Yes…a different DAC. Here’s the huge discussion:

http://forums.rokulabs.com/viewtopic.php?t=7009&postdays=0&postorder=asc&highlight=m1001+noise&start=0

Also in reference to your original question…if your source is lossless, the transcoding is really just “decoding” to pcm wav…so as long as your bandwidth can handle it, there should be no degradation in quality.

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