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Anyone seeing improvement with latest VLC player?

Discussion in 'Apple TV and Home Theater' started by nateo200, Dec 6, 2011.

  1. macrumors 68030


    I updated to the latest and most recent patch and my audio support is really improved! Before I could only get Pro Logic II over optical but now it passes 5.1 Dolby Digital to my receiver and properly decodes ALL the channels instead of just the matrixed Pro Logic II! Very pleased! I was always under the impression that 5.1 wasn't really usable over optical which made no sense to be but the technical reasons made sense I guess.

    Attached Files:

  2. macrumors 68030


    Ok even more impressive, I got 6 channel DTS discrete to pass over at a whopping 1500kbps! I'm really confused now! Not complaining though! Sounds amazing!

    In the attachments below it shows it. The blue light indicates multichannel decoding in progress. Everyone always told me it was impossible to pass more than 2 channels over optical?! Whats going on here?:eek:

    Attached Files:

    • DTS1.JPG
      File size:
      858.7 KB
    • DD1.JPG
      File size:
      824 KB
  3. macrumors 6502

    Everyone was wrong -- optical was basically invented to pass 5.1 discrete channels of Dolby Digital or DTS. Only 2 channels of uncompressed audio can be passed, but DD and DTS are compressed, so it's fine.
  4. macrumors 68030


    Ah ok I see! I guess they left out the uncompressed factor...what defines the barrier between "uncompressed" and "lossless" though? Like I know uncompressed is pretty much RAW and lossless is just lightly compressed or whatever, but for future reference what is the highest bit rate of various formats you can pass over optical? I mean I can get 1536kbps per channel with 6 channels of discrete DTS over or 640kbps Dolby Digital 5.1 now and obviously thats impressive, just curious when my decoder will become overwelhemed and do what it used to do and just down mix to Pro Logic II...I did try and play some TrueHD and it didn't work which is what I expected since my decoder is only 6.1 not 7.1...DTS-MA sounded much better than TrueHD though.
  5. macrumors 6502

    You're right, "uncompressed" is basically the raw audio in digital form, often called WAV or PCM or LPCM. It's the same as the studio master, say 5.1 channels of 24-bit audio sampled at 48 KHz = 6.9 Mbps. "Lossless" means this audio is compressed mathematically, so that when it's uncompressed it is exactly the same the studio master -- like a ZIP file can be compressed and then uncompressed without losing anything. TrueHD and DTS-HD MA are lossless formats.

    Dolby Digital and DTS are "lossy" formats, which means that they are compressed not only mathematically but also by throwing away parts of the audio you're not likely to notice. So they're not the same as the studio master, but the higher the bitrate, the less likely you are to be able to tell the difference -- like using more or less compression with a JPEG. You've already worked out the limits -- 640kbps for Dolby Digital and 1536kbps for DTS -- though that's not per channel, it's for all the channels in aggregate.

    Any multichannel format higher than Dolby Digital and DTS (e.g. DD+, TrueHD, DTS-HD) need to be carried over HDMI. If you're playing them over optical then only the legacy Dolby Digital or DTS track that usually accompanies them will be played.
  6. macrumors 68030


    Hmm okay thanks! Yeah I noticed with TrueHD, at least with the one video I have, unlike DTS-MA it does not have a 5.1 legacy track so with TrueHD my 5.1 decoder falls back to pro logic...I thought I would need a decoder with HDMI but it appears I can hold out! 5.1 surround is plenty for me.

    I definitely prefer DTS over Dolby Digital for the ultimate audio experience and Dolby if compatibility is needed. DTS seams like it has a wider "range" of sounds at 1536kbps...maybe its just my ears idk.

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