Two questions on encoding (Chapter Titles and simple Audio ?)

Discussion in 'Apple TV and Home Theater' started by 3282868, Apr 15, 2011.

  1. 3282868, Apr 15, 2011
    Last edited by a moderator: Apr 15, 2011

    3282868 macrumors 603

    Jan 8, 2009
    I've spent months learning and studying the process of converting full DVD rips into m4v's. My intent is to maintain near perfect quality of my DVD's. As such I am using custom settings in Handbrake that the CLI cannot use, negating the batch encode workflow from the provided guide. I am using Handbrake for each DVD rip, the m4v's will be stored on a local drive connected via ethernet to my aTV 2 and played through XBMC (tested and works perfectly).

    1. Tagging info:

    Need to tag my converted m4v's w/ actor(s), plot, movie poster, and most importantly chapter titles. I am using Handbrake nightly builds for each DVD rip (DVD rips on one SATA drive are encoded to another SATA drive in my Mac Pro). After Handbrake encodes the m4v, I can tag everything except for chapter titles as I cannot locate them online or through importing a .csv. I've searched everywhere, used Subler and MetaX to no avail. What am I doing wrong?

    2. Audio Tracks:

    1. English (AC3) (5.1), Codec AC3, Mixdown 6-Channel discrete, Samplerate Auto, Bitrate 640
    2. English (DTS), Codec AC3, Stereo, Auto, 256

    My Pioneer Elite VSX-33 system handles everything thrown at it, 7.1+, THX, DDII, etc. My intention is for the first track to maintain full audio quality for my surround sound system on my Pioneer AVR and Plasma, and a second audio stereo track for iDevices, etc. From my research I assumed AC3 is the best choice with 6-channel discrete to cover all my bases, or is AC3 Passthru the best in terms of keeping the DVD's full audio?

    Thanks for any help! :)
  2. EmpyreanUK macrumors regular

    Mar 6, 2011
    Similarly to you, I've also been learning how to make conversions of DVD rips that are as close to the original, both in terms of visual and audio and in terms of having full language and subtitle optionality. As such, I am by no means an expert on these matters.

    Having said that, my understanding is that AC Pass-Through would be the best option for your receiver, as it simply passes the full audio from the DVD, bit-for-bit, to the audio decoder.


    I realise you noted that you'll be playing these files on your Apple TV 2, but just so you know, should you ever want to play video files with AC3 pass-through audio on your Mac Pro using QuickTime X or iTunes, then you'll need to download and install Perian to be able to hear the audio.
  3. 3282868 thread starter macrumors 603

    Jan 8, 2009
    Thanks so much for your reply! It's not often people take the time in helping others so thanks :)

    AC3 Passthrough is one of the best, although I noticed that is select Auto in in Samplerate and 448 for Bitrate. I learned that if the option exists, 6-channel discrete with 640 bitrate is the best. So I've thrown in three audio layers (overkill I know lol):

    1 - AC3 with 6-Channel discrete, 48000, and 640 bitrate
    2 - AC3 Passthrough to test
    3. DD/Stereo

    So far everything is perfect, the sound is amazing, and XBMC passing the layers through to my Pioneer Elite VSX-33 with no issues and even sounds better than the SD DVD :)

    I have the newest Perian installed using Lion (developer here), and in Quicktime I make certain to chose "Language - 2 or 3" for the stereo layer otherwise it sounds like nails on a chalkboard lol.

    Thanks so much for your help!
  4. EmpyreanUK macrumors regular

    Mar 6, 2011
    Hey, no problem, sorry I couldn't have been more help! I've been racking my brains about all of this recently too, so I know how difficult it can be to find definitive answers!

    I'm glad to hear you've found a solution - and having three audio tracks doesn't seem like overkill to me, after all you only want to have to do this once :p I noticed that the bitrate selection box is greyed out and set to 448 when pass-through was selected, but I just assumed that it was because that was as high as DVD audio went - it seems I need to adjust my encoding settings now and do some experiments with 6 channels set to 640 :)

    Thanks for taking the time to reply with your newly found information!
  5. spacepower7 macrumors 68000

    May 6, 2004
    I would stick with the handbrake default AppleTV 2 preset for the audio.

    If you want to play on iOS devices besides the AppleTV, the the 2 channel aac track needs to be in the top of the list in the handbrake GUI.

    Wouldn't bother with 6 channel discreet audio but instead just use the ac-3 passthru. The .1 in 5.1 sound is the LFE (low frequency effects) aka the bass channel. Making that a full channel is just bloating the file with useless data.

    Stick with 5.1 ac-3 passthru because going 6 channel discreet is not going to improve the audio at all.

    As someone said in another thread, it's like trying to convert a compressed mp3 file into a lossless audio file. There will not be any quality gained but you will have a bigger file.
  6. 3282868 thread starter macrumors 603

    Jan 8, 2009
    Not so much the case. Here's what I learned and posted on another thread (and I know the .1 is the subwoofer, I have a B&W 7.1 system and believe me when I switch between audio tracks 1 − 6.1 − 2 - AC3 Passthru, there is a discernible difference):

    The lossless only has 5.1, from research you can pass it through to 6-channel discrete when offered and up it to 7.1 (Got B&W 7.1 SSS's with my Pioneer Elite system). To be certain, I've encoded the first track with a higher bitrate and the second just passthrough (from what I have learned passthru/passthrough isn't necessarily "lossless", and newer systems can "upcode" the audio - somewhat similar to older DVD players that could "upcode" SD to 720P - not truly HD). Having the three audio tracks allows me to make certain I'm covering my bases and I don't care about size as I have tons of it :).

    PS My iPad on iOS 4.3.1 plays the movies perfectly, through VLC of course ;)

    Thanks mate for the help!
  7. spacepower7 macrumors 68000

    May 6, 2004
    Ok I see

    Is it better to upcode via the Mac or let the Pioneer do it?

    Are you playing via the Mac to the Pioneer or from the AppleTV 2?

    If AppleTV 2, will it play the 6 channel discreet out of the optical or only HDMI? Could you test that for us, I like to know all of this nerdy stuff. :)
  8. The Mad Hatter macrumors 6502a

    The Mad Hatter

    Oct 12, 2004
    Wow, someone actually quoted me! :)

    Now bedifferent, I have to ask (since I'm still trying to get my head around your logic)... Are these rips you're 'up-converting' coming from a DVD or Blu-ray/HD-DVD? Because if it's a BR/HD then I understand the higher bitrate and 7.1 scenario. However, if you are taking about DVD, then how are you expecting to get 7.1 out of a format that is only capable of 5.1? I have seen DVDs do DTS, DTS-ES, etc., but not 7.1. So that is where my head is at in trying to figure you out. If there is a DVD doing 7.1, please, let me know. Until then, you're just wasting HD space (but hey, it's your HD space.)

    Just my opinion... And they do very. ;)

    PS. As for chapters, I use MetaX. 'Most' of the time it gets the chapter tracks through TagChimp.

  9. spacepower7 macrumors 68000

    May 6, 2004
    I'll quote you again ;)

    I'm trying to speculate if this is happening in the receiver or thru the AppleTV 2, thru optical or HDMI? Theoretically you can't get better than the 5.1 AC-3, but sending that signal different ways to the Pioneer receiver may yield different results. I'd like to know more too.

    As far as tagging, identify2 lite, not very lite at all, can get all the chapter names from themoviedb and tvdb. I just tried it today and it gives many features for free. I think I might pay the $10 just to have it rename tv episodes in the file name, not just the metadata.
  10. mbta3247 macrumors newbie

    Apr 19, 2011
    For chapters, I use Handbrake itself and usually just type them in by hand from the DVD's chapter menu. This is becoming less practical with newer stuff, as the studios have gotten lazy and stopped giving titles to each chapter on an increasing number of titles.

    When using CSV files, the spreadsheet (when viewed in that mode) needs two columns: the first with the chapter number, the second with the chapter title, and needs to have the same number of chapter entries as the movie you're ripping. This may mean adding an extra line at the bottom with a number but no title to deal with the <1 second-long blank chapters at the end of most movies.
  11. peterjcat macrumors 6502

    Jun 14, 2010
    That's cool, but just be assured that your additional 6-channel discrete track isn't doing anything. For a start, it's still only 5.1 -- that's what "6-channel discrete" means in this context, the five surround channels and the LFE channel each encoded separately rather than matrixed into stereo through Dolby Pro Logic II. Dolby Digital AC3 is only ever 5.1, and "upconverting" it to 640k is just like playing a vinyl LP and recording it onto a CD -- at its very best it's going to be the same, and technically it's always going to be slightly worse, because you're re-encoding an already-lossy encode with another lossy method, like photocopying a photocopy.

    AC3 Passthru is always 100% lossless in the sense that you get out exactly what you put in. The original AC3 is of course not lossless, it's a lossy encode of the original master. But the passed-through AC3 is exactly the same as what's on the DVD and cannot be improved.

    This is not to stop you from doing what you want, but making sure that other readers don't think they have to waste time, drive space and bandwidth adding extraneous audio tracks.
  12. AdrianK macrumors 68020

    Feb 19, 2011
    Agreed. A second AC3 track is redundant; passthrough AC3 if you don't already have it or encode as AC3 if you don't.
  13. 3282868 thread starter macrumors 603

    Jan 8, 2009
    Interesting. Thanks! I have noticed a difference and the 6-channel discrete plays in 7.1 versus the AC3 lossy passthru. Maybe it's a placebo effect (?), but on my Pioneer Elite VSX-33 it shows output to 7 channels and LFE. When I chose the second Passthru track in XBMC on my AppleTV 2 it sounds less robust.

    So technically this is what I should do:

    Track Codec Mixdown Samplerate Bitrate
    1. English (AC3) (5.1 ch) AC3 Passthru AC3 Passthru Auto 448 (Auto)
    2. English (AC3) (5.1 ch) AAC (CoreAudio) Stereo Auto 192-256 (?)

    That should be sufficient, and no need for 6-channel discrete? Why, perhaps, if 6-Channel discrete is offered and some state it's better is it not recommended?
  14. peterjcat macrumors 6502

    Jun 14, 2010
    It's there as an option primarily for encoding non-AC3 sources to AC3, so that files that originally had DTS or AAC 5.1 or FLAC or PCM or whatever can be played on the Apple TV... also I guess some people might want to save some space by reducing AC3 tracks to a lower bitrate.

    Since both AC3 Passthru and 6-Channel Discrete output a 5.1-channel AC3 track I can't see why your amp should treat them differently, it should matrix them both out to 7.1 in the same way... Maybe there are separate settings in your amp for 448k vs 640k but that would be surprising. Either way it's your amp that's doing any processing and nothing in the actual audio track. I don't have a Pio so can't be sure how exactly it's working there...
  15. rayward macrumors 68000

    Mar 13, 2007
    Houston, TX
    Ooops, answered a question that was, in fact, a statement. Nothing to see here...
  16. 3282868 thread starter macrumors 603

    Jan 8, 2009
    Quick question:

    Vorbis. What's the story behind that audio codec versus AC3?
  17. slothrob macrumors 6502

    Jun 12, 2007
    Do you mean AAC? Vorbis and AAC are two different compression algorithms.
    AC3 is Dolby Digital Audio, as audio is usually packaged on DVDs.

    Choosing AC3 Passthrough will place audio into the file without processing, which will give you the highest possible quality with the least possible artifacts.
  18. peterjcat macrumors 6502

    Jun 14, 2010
    Vorbis is free and open-source, which is nice, and Google has adopted it as the preferred audio component of its WebM container format, so it's likely we'll be seeing more of it -- though not on the Apple TV, which doesn't support it and probably never will.
  19. 3282868 thread starter macrumors 603

    Jan 8, 2009
    Ah, got it. Thanks guys! Some reason I thought Vorbis was related to higher quality audio with .mkv files (think I read that somewhere). Good thing I checked that info out.

    Thanks again for your help!

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