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Auricle
2004-05-30, 21:03
From a discussion back in April, I learned that the SB will support
48KHz playback. I have extracted the audio from a DVD (a series of DJ
mixes) to AC3. These files were converted to raw PCM and then
compressed with FLAC.

If I play these FLAC files on my SB, the audio sounds like it is being
played back too slowly.

I've confirmed that

flac -dsc --force-raw-format --endian=big --sign=signed filename.flac |
esdcat -r 48000

sounds correct (on the computer speakers). If I don't specify the
sample rate to esdcat I get the same "slow pitch" playback I hear from
the SB. The default rate for esdcat is 44.1KHz, so it *seems* like
SlimServer is making the same assumption on the sample rate.

I'm using the optical digital out of the SB and my external DAC says
the signal received is 44.1KHz.

Am I misunderstanding what is going on here? Is there something else I
need to do to get the correct sample rate?

This is using today's (5.30) nightly build of the server on MacOS X
10.3.4 and firmware V23 on the SB.

--jeff

--
auricle (AT) io (DOT) com

dean
2004-05-30, 21:09
Hi Auricle,

Indeed, SlimServer is assuming that the sample rate for uncompressed
(and converted) format is at 44.1k. This is a known bug and we'll be
addressing it.

Thanks,

dean

On May 30, 2004, at 9:03 PM, Auricle wrote:

> >From a discussion back in April, I learned that the SB will support
> 48KHz playback. I have extracted the audio from a DVD (a series of DJ
> mixes) to AC3. These files were converted to raw PCM and then
> compressed with FLAC.
>
> If I play these FLAC files on my SB, the audio sounds like it is being
> played back too slowly.
>
> I've confirmed that
>
> flac -dsc --force-raw-format --endian=big --sign=signed filename.flac
> | esdcat -r 48000
>
> sounds correct (on the computer speakers). If I don't specify the
> sample rate to esdcat I get the same "slow pitch" playback I hear from
> the SB. The default rate for esdcat is 44.1KHz, so it *seems* like
> SlimServer is making the same assumption on the sample rate.
>
> I'm using the optical digital out of the SB and my external DAC says
> the signal received is 44.1KHz.
>
> Am I misunderstanding what is going on here? Is there something else
> I need to do to get the correct sample rate?
>
> This is using today's (5.30) nightly build of the server on MacOS X
> 10.3.4 and firmware V23 on the SB.
>
> --jeff
>
> --
> auricle (AT) io (DOT) com

pkcrawford
2006-02-19, 11:51
I am having problems playing back flac files encoded at 48KHz. Is this still a known issue? Is there a solution?

dborn
2006-02-19, 18:18
I did something similar and I converted the ac3 to wav, converted 48KHz to 44.1KHz using ssrc_hp.exe and then used lame to convert it to mp3. I find the result quite acceptable.

You might use this (ssrc_hp.exe) as a temporary measure until the bug in slimserver/squeezebox) is fixed.

Daniel

crooner
2006-02-19, 23:44
I've experimenting with higher sampling rates encoding a few DADs (classic records 96/24 recordings) into FLAC files.

My laptop was able to play the 96 kHz 24 and 16 bit FLAC files.

However, the SB3 would play them at slow speed.

The higher I can go is 48 kHz and 16 bits resolution. 24 bits would cause the files to cut off. Presumably because of bandwidth problems. I am using a wireless connection.

pkcrawford: are you using 24 bits and 48 kHz by any chance?

bludragon
2006-02-20, 06:33
I have noticed similar issues - 48 kHz flac plays back at 44.1 kHz, and 24 bit flac skips. This is on a 100 Mbit ethernet connection.

pkcrawford
2006-02-20, 12:33
crooner,
My 48KHz files are at 16 bit.
Does this problem only happen with FLAC, or does it happen with all formats?

chrisal
2006-02-20, 16:17
Indeed, SlimServer is assuming that the sample rate for uncompressed
(and converted) format is at 44.1k. This is a known bug and we'll be
addressing it.

I have some 16bit 48khz files that seem to play fine on the sb2 over a wireless connection (i've not noticed any slow down or skipping). However I have noticed one problem and that is they don't play back gapless - I have a bug logged for this (#2990). I'm not sure if this is the same/related to/or nothing to do with the bug mentioned earlier in this thread - if it is related could this possibly be looked in to at the same time?

Thanks

Chris

gvh
2006-02-21, 02:22
I've just had 'fun' extracting tracks from various concert DVDs.

I use DVD Decrypter in IFO mode (in the Options - IFO mode tab) set the file splitting to By Chapter. Back on the main interface, in IFO mode, tick the Stream processing options and only tick the PCM stream. Click on the pcm stream and select the demux option.

When you decrypt you get one wav per chapter on the dvd.

Then use flac with plenty of -t options to flac them with the right meta data. I wrote a .bat file that I can post a sample of if you need it.

I also have bought Tag And Rename to fix any resulting mess.

Good guides here:
http://forum.digital-digest.com/showthread.php?postid=267286
http://www.doom9.org/index.html?/dvddec.htm


I find my sb2 plays 48khz flac at the right speed but my sb1 doesn't.

cheers

chrisal
2006-02-21, 03:42
I find my sb2 plays 48khz flac at the right speed but my sb1 doesn't.
cheers

gvh - do you find that the resulting files playback gapless or not on the sb2?

smst
2006-02-21, 04:14
Indeed, SlimServer is assuming that the sample rate for uncompressed (and converted) format is at 44.1k. This is a known bug and we'll be addressing it.
I see that this message is getting on for two years old. The bug in question is Bug#128 (http://bugs.slimdevices.com/show_bug.cgi?id=128), right? Is this still slated to be fixed?

chrisal
2006-02-21, 04:51
I see that this message is getting on for two years old. The bug in question is Bug#128 (http://bugs.slimdevices.com/show_bug.cgi?id=128), right? Is this still slated to be fixed?

Oops - I didn't check the date on that message - also it looks like bug #128 applies to the original squeezebox so I guess the 2 problems are not related. I wonder if there is a status update on both.

smts - have you experienced the lack of gapless on your 48khz dvd rips too? I'm trying to find out if it's just me but I got no responses from a previous thread either....

gvh
2006-02-21, 06:23
gvh - do you find that the resulting files playback gapless or not on the sb2?


I'll let you know in a couple of days. About to be to be away on a work trip.

I was thinking of wiki'ing my experiences. Any objections?

smst
2006-02-21, 08:22
smts - have you experienced the lack of gapless on your 48khz dvd rips too? I'm trying to find out if it's just me but I got no responses from a previous thread either....I haven't tried it actually -- the only DVD rips I have as FLAC are discrete songs anyway. I'll try it out with concert footage if I can find the time; you're just grabbing the stereo, not the 5.1 mix, right?

chrisal
2006-02-21, 12:02
I haven't tried it actually -- the only DVD rips I have as FLAC are discrete songs anyway. I'll try it out with concert footage if I can find the time; you're just grabbing the stereo, not the 5.1 mix, right?

Well I've actually tried ripping a 5.1 mix to seperate ac3 files then converting it to wav using your your utility (thanks btw) then encoding the files to flac and tagging them. The resulting files are 16bit 48khz flac files which playback fine in full surround sound except for the small but noticable gap between tracks that should be seamless.
At first i though this was a problem because of the DD encoding but by coincidence i've got some other 48khz 16 bit files from a live recording that hasn't been anywhere near 5.1 dolby digital and they playback fine except for the gap which is exactly the same sort of gap as i get with the 5.1 files.
So I concluded that the problem is with 48khz files rather than the DD 5.1 encoding. It's bug #2990 if you want to vote for it ;-)

let us know how you get on either with stereo or 5.1 48Khz rips. It would be very nice to have this fixed as a lot of DVD based music is of live recordings that benifit from gapless playback.... It's as near as damnit already but this would pretty much make the SB2 perfect in my book!

crooner
2006-02-21, 16:43
I haven't tried other formats, I guess because raw WAV files would be huge and use a lot of bandwidth.

I ripped my DADs (which are actually DVDs with audio only) using DVD audio extractor. Great software!


crooner,
My 48KHz files are at 16 bit.
Does this problem only happen with FLAC, or does it happen with all formats?

Patrick Dixon
2006-02-22, 10:44
I have tested the latest nightly (22 Feb), which includes an SB2/3 Firmware update to V35, and 48KHz 24bit FLAC and WAV playback appear to work fine.

Thanks to Dean I think.

abdomen
2006-02-22, 12:02
I have tested the latest nightly (22 Feb), which includes an SB2/3 Firmware update to V35, and 48KHz 24bit FLAC and WAV playback appear to work fine.

Thanks to Dean I think.
I haven't tested it myself yet, but that is great news. Thank you, Dean!!

smst
2006-02-22, 13:24
Well I've actually tried ripping a 5.1 mix to seperate ac3 files then converting it to wav using your your utility (thanks btw) then encoding the files to flac and tagging them.You're welcome!

Anyway, I've tried it out and I also get the gap between FLACs. I updated to the latest nightly for that new firmware and I still get a gap between AC3.FLAC files; I haven't tried stereo files since the update.

(And that new firmware appears to solve my full-bitrate DTS issues too, which is extremely pleasing!)

Renyao
2006-02-22, 22:20
16bit/48khz wav or flac files don't play well still with the
2006/02/22 nightly.

16bit/48khz wav files play slowly ;
16bit/48khz flac files play with gaps at the start of almost
all tracks;

I have same experiences with chrisal.

dean
2006-02-22, 22:38
Renyao, do you have example files that I could get to try to reproduce the problem? Send me email to dean@slimdevices.com

chrisal
2006-02-23, 03:04
16bit/48khz wav or flac files don't play well still with the
2006/02/22 nightly.

16bit/48khz wav files play slowly ;
16bit/48khz flac files play with gaps at the start of almost
all tracks;

I have same experiences with chrisal.

Just to confirm - i tried with firmware 35 with both wav and flac and the gap is still there with 48khz.
I can send a couple of example files - how do i submit? - using attachments on the bug?

chrisal
2006-02-23, 16:00
Renyao, do you have example files that I could get to try to reproduce the problem? Send me email to dean@slimdevices.com

I have posted two files on bug 2990...

Cheers

Chris

Renyao
2006-02-23, 20:31
I did several experiments yesterday and confirmed that
wav file playing in SB2 is smooth and gapless ,while flac file playing in SB2 has gaps between tracks no matter in 44.1khz or 48khz the files are.

I cut a 5 seconds long segment from a CD track starting at the beginning of the track.The segment is named "01 16bit-44.1Khz music-segment.flac".

"01 16bit-44.1Khz music-segment.flac" is 5 seconds long and has
44100*5=220500 samples.This segment plays well in SB2 in native
flac or wav format.

I then cut the segment "01 16bit-44.1Khz music-segment.flac" into two parts.They are segments "02 16bit-44.1Khz music-segment-part-one.flac" and "03 16bit-44.1Khz music-segment-part-two.flac"

"02 16bit-44.1Khz music-segment-part-one.flac" has 117600 samples
and is approximately 2.67 seconds long,while "03 16bit-44.1Khz music-segment-part-two.flac" has 102900 samples and is approximately 2.33 seconds long.

I then Add "02 16bit-44.1Khz music-segment-part-one.flac" and "03 16bit-44.1Khz music-segment-part-two.flac" to playlist.And Then begin playing these two segments in REPEAT-ALL mode.

When the server transcoding "flac --> wav" is checked,the sound from the speakers is very smooth as if the two music segments were one 5 seconds long segment only.No gaps at all.

When the server transcoding "flac --> flac" is checked,however,the sound from the speakers has gaps between these two segments.Sometimes the gap is tiny and sometimes the gap is rather big and it is different almost every time.This phenomenon becomes severer with 48Khz flac files.

I Thought I could upload the 3 files for you to test.But the file size for uploading is limited to about 97kB.I failed to do
that.

However I think You can make your own segments and confirm it.

chrisal
2006-02-24, 07:47
I did several experiments yesterday and confirmed that
wav file playing in SB2 is smooth and gapless ,while flac file playing in SB2 has gaps between tracks no matter in 44.1khz or 48khz the files are.


Hmm - I'll double check again tonight to make sure but I'm 99% certain my 44.1khz stereo flac files are playing back gapless.
Renyao - Perhaps you have another issue....

chrisal
2006-02-26, 08:15
Hmm - I'll double check again tonight to make sure but I'm 99% certain my 44.1khz stereo flac files are playing back gapless.
Renyao - Perhaps you have another issue....


Yep - my 44.1khz flac files definitely play back gapless....
Using firmware 35 currently and I'm certain it worked ok before I upgraded too.

chrisal
2006-03-10, 04:32
I have posted two files on bug 2990...

Cheers

Chris


Bump - just wondered if there had been any progress!

Cheers

Chris