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Author Topic: why no WAV transcoding for Upnp server?  (Read 2535 times)

highgrovemanor

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why no WAV transcoding for Upnp server?
« on: December 28, 2005, 11:30:15 am »

I was a pretty hardcore media jukebox user awhile ago, and have 95% of my music in APE files.  I now have an IO-DATA DVD player and would like to stream music.

Does Media Center 11 offer any other transcoding options besides mp3?  My perfect world is to save disk space using APE or FLAC, and serve up lossless audio via WAV...if I can't do this today, is it in the works for a future release?

Media Center is very close to matching my needs, provided I can serve up full fidelity WAV files & I can find the time to looking into the tivo interface.


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Myron

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Re: why no WAV transcoding for Upnp server?
« Reply #1 on: December 28, 2005, 02:16:15 pm »

I seem to remember that transcoding to WAV was available a long time ago when MC 11.0 was in beta.  It's not an option now.  Not sure why.

I'd also like to see transcode to WAV become available again...
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highgrovemanor

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Re: why no WAV transcoding for Upnp server?
« Reply #2 on: January 04, 2006, 09:41:58 pm »

No jriver response makes me think its not in the works either, so I guess I better start looking elsehere..
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Alex B

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Re: why no WAV transcoding for Upnp server?
« Reply #3 on: January 05, 2006, 07:26:24 am »

Can you use MC's server with your IO-DATA DVD device? Is it a standard UPnP device?

I wonder if the wave format has some technical limitations that make it unsuitable for MC's UPnP server.

MP3 at CBR 320 kbps would be almost the same as a lossless format for listening purposes (when converted from a lossless source). I doubt anyone can hear the difference with standard music tracks in casual listening. In blind listening tests even the trained listeners need to use specific short problem samples and high quality headphones for hearing any artifacts.

The lack of true gapless playback is in my opinion a bigger and clearly audible problem with MP3 files, but I think the standard UPnP devices may have that problem with any file format.

EDIT

If there are no technical reasons for not having the wave option it should be returned. On a high speed local LAN it makes no sense to recompress the files after decoding. The server may have better use for the processing power.
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Myron

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Re: why no WAV transcoding for Upnp server?
« Reply #4 on: January 05, 2006, 08:32:00 am »

I wonder if the wave format has some technical limitations that make it unsuitable for MC's UPnP server.

I don't see why this should be the case.  MC can serve WAV files without transcoding, that's all I use.  Maybe I just don't understand the complexity of the problem?

The option to transcode to WAV was available at one time - I remember trying this option with my Philips Streamium and it did work.  The Streamium did not support WMA at the time and I was able to play WMA files by transcoding to WAV.

I think most players support WAV.  Certainly more support WAV than APE and FLAC.  It doesn't make much sense to take a lossless format and force a lossy compression.  For streaming APE files in MP3, doesn't it require two conversions, APE to PCM and PCM to MP3?  Seems it should be less complicated to do only one conversion, from APE to PCM and then just re-format to WAV.  Or am I just oversimplifying?

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Alex B

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Re: why no WAV transcoding for Upnp server?
« Reply #5 on: January 05, 2006, 08:36:22 am »

It doesn't make much sense to take a lossless format and force a lossy compression.  For streaming APE files in MP3, doesn't it require two conversions, APE to PCM and PCM to MP3?  Seems it should be less complicated to do only one conversion, from APE to PCM and then just re-format to WAV.

I agree. That's why I added the edit to my reply.
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Alex B

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Re: why no WAV transcoding for Upnp server?
« Reply #6 on: January 05, 2006, 08:51:16 am »

Also, the wave option would be usefull if the files are already in a lossy format that is not supported by the device. Transcoding the files to another lossy format would needlessly reduce the quality.

EDIT

Personally, I would like to use the wave option with the Library Server/Clients if it could make my APL and CUE tracks playable through the server. The server could decode just the specified part of the CD image file and send it to the client. Currently I am forced to use shared network folders and local copies of the main library instead.
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Myron

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Re: why no WAV transcoding for Upnp server?
« Reply #7 on: January 05, 2006, 10:16:30 am »

OK, so we're on the same page on this. :)

All we need now is some feedback from J River:

Is transcoding to WAV reasonably feasible?  If so, is or can it be on the list for future release?
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John Gateley

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Re: why no WAV transcoding for Upnp server?
« Reply #8 on: January 05, 2006, 10:22:36 am »

Hi Y'all, I'm looking at this. Going from memory, WAV was removed because the encoder has to prepend information after writing the content (seeking to the beginning). I'll look at it to see if my memory is working, and if I can fix it...

j

John Gateley

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Re: why no WAV transcoding for Upnp server?
« Reply #9 on: January 06, 2006, 03:20:55 pm »

Hi Y'all,

Sorry, but I remembered correctly. The WAV header is written after the WAV data is produced, so it's not a streaming format. I may be able to do something in v12, but not in 11.1

j

timothyc

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Re: why no WAV transcoding for Upnp server?
« Reply #10 on: January 25, 2006, 11:32:46 pm »

John,
I'm not an expert at any of this, but I think what is meant by transcoding to WAV is not streaming of the Microsoft WAV file itself with header/wrapper, but the underlying LPCM data only.  I think most of the upnp renderers can receive and decode an LPCM stream, including the 3 Roku's I have.  The Rokus report "WAV" as the uncompressed format, but I think they are actually just rendering LPCM with metadata provided by the server. Twonky and other servers I have tried are able to transcode to an uncompressed stream with no problem, so maybe there is a simpler way to implement this (or maybe I don't know what I'm talking about, which is likely)  I thought you had it working at one time a while back, didn't you?
T
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John Gateley

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Re: why no WAV transcoding for Upnp server?
« Reply #11 on: January 26, 2006, 12:12:42 am »

Hi Timothy,

You are correct (I think), but I can't do anything until 11.1 is done.
We did have it at one point, but it would write extraneous data at the end (the header info that should have been written at the beginning). We had problems with non-streaming encoders and when I put in the test, WAV was one of them. I will look at this later, feel free to bump it to remind me.

j
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