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7th January 2011, 22:05 | #1 | Link |
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DTS (& 640kbps AC3) encoding software questions, esp. as re. Blu-ray
It seems like some people who likely find DTS 1.5Mbps a sweet-spot for quality vs. bitrate for surround-encoding are reencoding some of their lossless BD audio tracks to core DTS for their backups using BD-RB, or going to MKV, etc. I am considering this route myself (generally to BD25 via BD-RB), but have some questions for those in the know.
As of right now, the SurCode DVD-DTS application is $249 direct from the developer (slightly cheaper elsewhere). It seems to encode 1.5Mbps/756Kbps 48Khz streams, and DTS-CD compatible 44.1Khz streams. I'm fairly certain some people use this encoder app for Blu-ray backup audio reencodes. DTS's own DTS Surround Audio Suite is also exactly $249 at the moment, and has all the functionality of the SurCode app, plus support for DTS-ES Discrete and DTS 96/24 (both of which are backwards-compatible with standard DTS-capable devices/decoders). It, however, has some caveats listed on the site: In comparing the regular DTS encoder and their DTS-HD encoder, they state the following on their FAQ page: DTS-HD Master Audio Suite (MAS) is capable of encoding all DTS-HD™, DTS Express™, and DTS Digital Surround™ audio stream types for Blu-ray Disc™, DVD, and DTS Music Disc. DTS Surround Audio Suite (SAS) is specifically suited for standard definition optical media, such as DVD and DTS Music Disc, but cannot produce Blu-ray Disc compatible stream typesOn the surface, this seems in contradiction to the answer to a question a few lines lower on the same FAQ: Can DTS be the only audio stream on a disc?But again, lower still, we have these two answers: Which types of DTS-HD or DTS streams are compatible with which type of optical media?So, is DTS just trying to hard-sell the (far) more expensive suite by outright lying, or is there a grain of truth in this, such as that technically the file/format output by the less expensive software won't work with BD unless somehow tweaked? If tweaking is necessary, are there free apps to handle this? Are the files output by SurCode, on the other hand, fully ready to be loaded into a Blu-ray authoring app? Next issue: Does anyone have any objective/subjective comparisons on the quality of the DTS 1.5Mbps encodes of the SurCode app vs. DTS's own DVD-DTS suite, or are the algorithms in the two apps identical (and deterministic) such that any identical inputs and parameters will result in identical outputs from each app? And finally: Seeing as how encoding to BD-compatible 640 kbps AC3 is possible for free using Aften (eac3to) etc, can anyone here comment on subjective/objective audio differences in encodes to 1.5Mbps DTS vs 640 Kbps AC3, especially any A/B listening experiences of encodes from an identical lossless source? Thank you all. :-) |
8th January 2011, 03:32 | #2 | Link |
Skittle
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You dont need to re-encode or pay out the butt for this feature!
You can extract the DTS core with eac3to or other free tools. Or you could go the MKV route and choose FLAC and/or keep the DTS-HD/DTS tracks. regarding dts vs AC3... you will find mixed opinions about which is better, warmer, accurate, more depth etc... but generally they're are about the same with AC3 taking much less bitrate. |
8th January 2011, 03:57 | #3 | Link |
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Thanks--I fully plan on just pulling off the core DTS track any time one is available, as that does make the most sense when it's possible.
I guess I should have clarified that I was referring to discs with multichannel LPCM or Dolby TrueHD tracks, since in the former case there may or may not be a lossy surround track at all or it may be low bitrate, and in the latter case the AC3 stream tacked onto the DD-THD stream may be encoded at a bitrate lower than the 640 kpbs max allowed for Blu-ray. Also, my target medium is BD25, so unfortunately I can't use the superior FLAC lossless compression. |
8th January 2011, 05:07 | #4 | Link |
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Just assembled a disc in Scenarist BD with a .cpt DTS file from a DVD project (1.5mb) which was created back in 2007 with a 'pre-HD disc' encoder.
Scenarist took it without complaint, muxed the disc, and it plays fine (in PowerDVD at least)... I'm pretty sure that DVD-encoded AC3 and DTS are 100% compatible with Blu-ray... Maybe not every authoring software is programmed to accept the .cpt file format... Other than that possibility, I can't imagine why they would say it's not compatible (other than hyping sales of the HD software...) For AC3, I don't think I've ever seen a Blu-ray disc with less than a 640k legacy stream (not that I've looked in detail)... That would be very lame. Possible, yes, but I believe very rare... |
8th January 2011, 07:39 | #5 | Link |
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@rik1138: Thank you! I appreciate your effort in confirming that suspicion.
I haven't looked at my Blu-rays with an eye towards the AC3 bitrates, but I really hope you're right, since I get the impression that 640k AC3 and 1.5M DTS are both generally considered perceptually near-lossless. I'd like to meet that goal without having to purchase additional software. |
8th January 2011, 11:03 | #6 | Link | |
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Quote:
Even those playing it on a PC still have to fight several hurdles in order to get lossless HD audio digitally out (the cheapest audio card with HDMI or video card with HDMI-audio is ~300€, 2-3x the price of an entry level BD player). 5.1 is the easiest way of having high quality audio, without too much trouble. So they are generally forced to do this, it's not their choice as you thought it were. * Popcorn Hour, some models, at least 350€ bare HD Dune, some models, at least 500€ Sony PS3, at least 300€, cinavied vs WD TV ~ 80€ China-noname ~ 60-100€ (according to the rebadger) even some entry level USB-enabled BD players (lots of restrictions though) ~ 100-150€ |
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8th January 2011, 13:00 | #7 | Link | |
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As rik1138 said there are some rare examples where this isn't the case (LPCM / TrueHD with <640 AC3 or DTS-HD with a half rate core) but they're so few and far between that (IMO) it's not worth shelling out money in order to transcode. I'd just live with the lower rate, or if you do transcode then use a free solution such as Aften. No point in worrying about it anyway until you actually find a disk where this is the case |
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8th January 2011, 17:17 | #8 | Link | |
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A lossless track is much bigger, less compatible and people are often unable to distinguish between that and a high bitrate encode (e.g. AC3 640 kbps). I have a WD TV and while it would be nice if it supported more formats like DTS-HD I'd never use that functionality. |
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8th January 2011, 18:49 | #9 | Link | |
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The lossless HD audio both on mediaplayers and PC is extremely cumbersome, even if converted into FLAC. The only feasable way of using lossless HD audio is to burn it on a BD video (along with the video track to whom it belongs) and play it on standalones (hopefully not "cinavied"). So, people are forced to use 5.1 lossy because of: 1. the available space 2. multiple issues with HD lossless on PC 3. unsupported format on most mediaplayers Both this post and the other one should be understood as "no, people do not reencode to lossy", but as "people keep the lossy", not only because the access to 6 true channels is beyond the monetary reach of a consumer, but also because 6 chn. encoding software play in the same league. |
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9th January 2011, 13:26 | #11 | Link |
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Not sure if you have stumbled across this link or not, but it's an interesting study done by European broadcasters (the pretty graphs start on page 21!):
http://tech.ebu.ch/webdav/site/tech/...h/tech3324.pdf For those too lazy to click the link, basically the "Original ANC", "DTS 1500" and "DD+ 448" (AC3 640kbps) tracks all score 92-95% on the perceived quality score (so the lossless formats should score the same as "ANC_Original"!) ... 7ek |
10th January 2011, 21:58 | #12 | Link | |
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They wouldn't go above 448 for DVD, so I guess that can be a problem with older titles. Hopefully even that practice (if it existed) is being phased out... |
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10th January 2011, 22:53 | #13 | Link | |
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http://www.newegg.ca/Product/Product...-358-_-Product |
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11th January 2011, 00:32 | #14 | Link | ||
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A few more questions come to mind: * Has anyone here bothered using Aften/eac3to to reencode to AC3@640 for similar reasons, and if so did the resulting file sound more transparent to the high-def/lossless source than did the (presumably) low-bitrate compatibility track that had been used alongside/within the HD/lossless? * Has anyone ever had any compatibility problem with Aften-encoded AC3 tracks (via BD-RB/eac3to etc) on hardware decoders (BD player, HT receiver)? * Are BD players set to bitstream via SPDIF actually streaming 640kbps AC3 tracks at full bitrate, or stripping it down to 448 somehow for compatibility with older receivers, seeing as how until BD/HD-DVD, no consumer devices I'm aware of really output 640 kbps AC3? Has anyone ever happened across an older DD/AC3 receiver that didn't support/function with bitstreamed 640 kbps AC3? |
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11th January 2011, 03:01 | #15 | Link | |
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11th January 2011, 06:44 | #17 | Link | |
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11th January 2011, 09:35 | #20 | Link |
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This Dutch site sells the HD5450 for 32 Euros.
http://www.komplett.nl/Komplett/prod...Z/default.aspx |
Tags |
ac3, aften, blu-ray, dts, surcode |
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