DTS @ 1.5 mbps = stuttering

[superjunior]

When i playback movie files with a DTS track with a high bitrate, approx 1.5 mbps, the sound stutters. This only happens when the computer is connected to my receiver through SPDIF.

Is this solvable if I change some settings in the preferences or will this be fixed in the next release?

[Ayla]

I have the exact same problem!

High bitrate DTS stutters, connected with SPDIF to my receiver.

Any solution?

[superjunior]

Have anyone of the VLC developers acknowledged this problem?
Are you looking into this?

This is probably a bigger problem for VLC users than it seems in this forum, since most users cannot find the source of the problem. For me VLC is soon rendered useless since most material I watch contains a high bitrate DTS track. I really like VLC and want to continue using it.

Would be nice with some response from any developers on your status concerning this issue.

Thanks.

[Arite]

As far as I know there is a general problem with S/PDIF output.

However, you could try raising the file cache. To do this go to:
Settings >> Preferences... >> Input / Codecs >> Access modules >> File

Then tick "Show advanced options". Enter a larger value for "Caching value in ms" (e.g. 1000) and press "Save". You may need to restart VLC, then try playing DTS through S/PDIF.

If that doesn't make any difference then you could test out one of the latest VLC nightly builds (0.9.0-svn):
http://nightlies.videolan.org/

Cheers, Arite.

[krill]

I too have experiened this problem, buffering does not seem to help... video just randomly crashes..

Have tried a few different versions and many settings within VLC..

[superjunior]

As far as I know there is a general problem with S/PDIF output.

However, you could try raising the file cache. To do this go to:
Settings >> Preferences... >> Input / Codecs >> Access modules >> File

Then tick "Show advanced options". Enter a larger value for "Caching value in ms" (e.g. 1000) and press "Save". You may need to restart VLC, then try playing DTS through S/PDIF.

If that doesn't make any difference then you could test out one of the latest VLC nightly builds (0.9.0-svn):
http://nightlies.videolan.org/

Cheers, Arite.

Thanks, but I already set the cache to 5000 ms, it doesn't help.
Nightlies show no improvement either.

[Qlone]

I have the same problem here.

Today I decided to take a look at it, and built the latest VLC from the SVN repository. Here are my findings so far:

- The DTS to SPDIF code wraps the DTS stream in SPDIF frames, for some reason it does so 3 at a time...
- This works OK for small frames (low bitrate DTS), but causes stuttering for high bitrate DTS streams, even though all the data (2013 bytes) fits in the SPDIF frames.
- This wrapping is not neccessary for most receivers, so I removed it. The result is exactly as it was before; low rate DTS streams are OK, but full rate streams stutter...

I was hoping to find a simple bug where the author of some code just didn't allocate enough space for the high bitrate stream's larger buffers but that doesn't seem to be the case. I've looked into the dtstospdif.c code and into codec/dts.c.

I also tried this on Windows, with the latest VLC release. High rate DTS over SPDIF also fails there, but there are alternative players on Windows. On OSX we don't seem to be that lucky...

[Jean-Baptiste Kempf]

You should post that to vlc-devel@
This is interesting and we are interested in your findings/patches.

[Qlone]

- Also, the SPDIF's bitrate is set to match that of the DTS track. I believe this is not correct, since the SPDIF is only used as a transport channel and has no relation to the contents of the bit stream it is transporting. Out of this bitstream a multi channel 48khz audio signal can be reconstructed.

Edit: I take that back . Apple's DVD player application also sends out an 48khz sample rate when playing a DTS track over SPDIF. My DTS audio cd's however don't, and they are 1.5mbps DTS... hmm...

- Sadly, setting the stream to 44.1khz does not fix the stuttering...

[simondo]

this also happens to me; macbook, 2.16 intel, leopard, 2GB. DTS is choppy - more corrupted than stuttering.

any resolution would be appreciated!
any assistance anybody needs, just ask

si

[Ayla]

Any news on this?

VLC developers - anyone out there?

[davidgilmour]

this also happens to me; macbook, 2.16 intel, leopard, 2GB. DTS is choppy - more corrupted than stuttering.

any resolution would be appreciated!
any assistance anybody needs, just ask

si

MacBook 2.0 intel, leopard 2GB and Mac Mini 1.83 Intel, leopard 1GB.

I can confirm that DTS @ 1.5 Mbps sounds cracky in VLC. Never noticed this before but I just found out in the Queen Montreal/David Gilmour RAH rips. Time to leave the Mac OS X platform and go to Windows for us OS X users?

p.s. no receiver connected, the sound goes direct from the Mac to the TV and it's cracky.

[simondo]

I can confirm that DTS @ 1.5 Mbps sounds cracky in VLC. Never noticed this before but I just found out in the Queen Montreal/David Gilmour RAH rips. Time to leave the Mac OS X platform and go to Windows for us OS X users?

p.s. no receiver connected, the sound goes direct from the Mac to the TV and it's cracky.

I find the contrary, when I don't choose encoded output from files with a DTS soundtrack, it comes out fine from my amp, obviously not in DTS, and - I think - suffering a little bit from being encoded on the fly into something that can be sent down the optical wire to my amp.

[rickeo]

Intel iMac 2.0Ghz Core Duo 2Gb RAM 512Mb ATI X1600

Experiencing the same issue.

Video of the problem= http://s89.photobucket.com/albums/k215/ ... 066avi.flv

[ToeCutter]

Try those high bit rate DTS tracks on MPlayer. It seems to work fine with 768kb DTS tracks.

viewtopic.php?f=12&t=42070&st=0&sk=t&sd=a&start=15

[jnmen]

Problem has been identified and fixed by the devteam (viewtopic.php?f=12&t=42070&st=0&sk=t&sd ... 30#p135587). We now have to wait for a new build of VLC for the Mac.

[zipdox]

I still have this issue. I updated to nightly and it still stutters.