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BJBBJB1
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Maximum Blu-Ray length at HQ with H.264 and 5.1 audio

Aug 12, 2012 8:27 PM

Greetings,

 

I am trying to get through my first project after upgrading to CS6 and although I have searched on this topic, I have not found a solution.

 

I previously used CS5 and encoded with MPEG-2/HQ/VBR2 to 1440x1080i (matches the source) and Surcode encoding for 5.1 audio to produce Blu-Ray's.

 

It seems like with CS6, and the enhanced video codecs, the momentum is to start using H.264 vs. MPEG-2.  Do I have that correct?

I am aware there seem to be some issues with 5.1 audio and the various encoding presets but I don't care as I have to encode my audio and video separately in order to get them into Encore.  Can't believe we STILL have to do that....

 

Anyway, if I am correct that the preferred method is to use H.264 now, then my question is this: 

 

What is the maximum high quality project length (that will fit on a SL BD disc) if I use H.264 as the encoder to 1440x1080i, high quality, with a 5.1 audio soundtrack?  My source material is HDV if that matters.  I guess a related question is with H.264, what are the recommended settings/bitrate in order to get maximum or high quality with that codec?  I had this all figured out for MPEG-2!

 

Thanks for any insights,

 

BJBBJB1

1736 Views   5 Replies   Latest reply: BJBBJB1, Sep 10, 2012 9:52 PM
 
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  • BJBBJB1
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    1. BJBBJB1,
    Aug 12, 2012 9:16 PM   in reply to BJBBJB1
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    I also have one additional question.  With CS5 I encoded to 1440x1080i for my blu-ray discs....technically using AME to encode and then add menus and create the blu-ray image without any further video scaling.

     

    This seemed to be the recommendation I had for HDV footage going to Blu-ray and I created some nice looking discs.

     

    But, in conjunction with my question above on changes for H.264, does cs6 change the recommendation on what resolution to use in AME for HDV source fooage?  That is have the encoder do the scaling vs. the bluray player?

     

    Thanks. Again, appreciate any input. Struggling trying to determine my multi-disc cut points without being able to fit out the disc lenghts above.

     

    BJBBJB1

     
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  • BJBBJB1
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    2. BJBBJB1,
    Aug 15, 2012 3:58 PM   in reply to BJBBJB1
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    If anyone had even a partial solution or suggestion it would be appreciated. I have googled, looked at Adobe resources and I am at a loss.  I guess if there is no input I will just have to cut the video at an even half and forget trying to do a smart disc change break based on content....

    I've looked at the calculators (outdated codecs), or they don't handle 5.1.

     

     

    BJBBJB1

     
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  • A.I.1
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    Feb 20, 2012
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    3. A.I.1,
    Aug 18, 2012 9:36 PM   in reply to BJBBJB1
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    It's an interesting question, though I don't have AME CS6, only AME CS5.5.

     

    I don't think the video codec should really matter for calculation of amount of space taken up at a particular bitrate, though if you're using a higher bitrate for the audio, that will matter.

     

    eg. a video (no audio) of a particular duration, encoded with an average bitrate of 20 Mbps with the H264 video codec would take the same amount of space as a 20 Mbps video (no audio) encoded with the Mpeg2 codec.

     

    These are rough figures: 

    eg. (all other things being equal):

    A 2 hour Mpeg2 video encoded at an average of 20 Mbps would take about 17.58 GB

    A 2 hour H264 video encoded at an average of 20 Mbps would also take about 17.58 GB

     

    It seems like with CS6, and the enhanced video codecs, the momentum is to start using H.264 vs. MPEG-2.  Do I have that correct?

    I don't have CS6, but, in terms of picture quality at a given bitrate, H264 should give a better quality picture than Mpeg2.  (as a very rough idea - and this might not be totally correct but, I think at low bitrates (around 10 Mbps?) H264 is supposed to be equivalent to an mpeg2 of about double the bitrate).  eg. 10 Mbps H264 might look about the same as a 20 Mbps Mpeg2 video.  Though at a lot higher bitrates and the same HD resolution, the difference will be less or, if high enough bitrate, there probably won't be a difference).

     

    BJBBJB1 wrote:

     

    What is the maximum high quality project length (that will fit on a SL BD disc) if I use H.264 as the encoder to 1440x1080i, high quality, with a 5.1 audio soundtrack?  My source material is HDV if that matters.  I guess a related question is with H.264, what are the recommended settings/bitrate in order to get maximum or high quality with that codec?  I had this all figured out for MPEG-2!

     

    I don't have CS6, but I suppose it also depends on how much space the audio track takes up.  Are you using a lossless audio codec or a lossy one?  About what average bitrate is your audio (if lossless it will depend on what is in your audio track)?

     

    Apart from if it's using a higher bitrate for audio, the duration you can fit on with H264 would be the same as with Mpeg2 - though as H264 should give you a better picture quality than Mpeg2 at the same bitrate, you could probably lower the video bitrate compared to how you would have with Mpeg2.

     

    My rough calcs (may not be totally correct):

    Total Average Bitrate 18.9 Mbps would give you about 3 hours of video with audio on a 25 GB disc (say if audio was about 4.1 Mbps and video was 14.8 Mbps).

    Total Average Bitrate 28 Mbps should give you about 2 hours of video with audio on a 25 GB disc

    Total Average Bitrate 35 Mbps should give you about 1 hour 37 mins of video with audio on a 25 GB disc

     

    ---

    In the preset for "Bitrate level: High" in CS5.5, with a resolution of 1440x1080, with Profile High, level 4.0/4.1,  it gives a target bitrate for video (not audio) of 18.75 Mbps

     

    If we assume audio is about 4.1 Mbps (the actual value will depend on the actual Mbps of your audio),

    that would give a total (video+audio) average bitrate of 18.75+4.1 Mbps = 22.85 Mbps

     

    At 22.85 Mbps total for the average bitrate, that should give you around 2 hours 29 mins (ie. about 24.94 GB), though you'd need to leave a bit of disc space for menus (maybe assume the durations you could fit on are slightly less than this to be safe).

     
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  • BJBBJB1
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    4. BJBBJB1,
    Aug 18, 2012 9:49 PM   in reply to A.I.1
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    Thanks so  much for putting in the effort for this detailed response!  You have really helped me out a lot with my thought process.

    I know I had read with CS5 with a 1 hour HD Blu-Ray project to use VBR2, if over an hour use H.264.  I guess as we learn more about CS6 we'll see if at lower bitrates, there is an improvement.

     

    Since I try to render and fairly high bitrates, it seems like there would not be much difference....unless I could test and figure out for my footage at what bitrate H.264 gives the same quality as a high bitrate VBR2 project.

     

    Thanks again,

    BJBBJB1

     
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  • BJBBJB1
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    5. BJBBJB1,
    Sep 10, 2012 9:52 PM   in reply to BJBBJB1
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    Certainly A1i answered just about everything I could want above, but thought I would also post my experience in case someone comes across this thread with the same question.

     

    Using MPEG-2, 2-pass, I was able to fit a 1 hour 40 minute "mixed-subject" source project (so not a football game, but not a static image either) onto a SL BD disc at high quality preset and maximum render quality with a 5.1 soundtrack with 2GB to spare. Very nice output quality. I think I goosed the 3 bitrate choices up just a bit from the preset since I had the room.  I think if I went over this length, I would switch to the H.264 codec and ramp down my bitrates.

     

    Only issue I had was when I took my resulting video into Encore CS6, it IMMEDIATELY wanted to transcode my 1440x1080 video even though my Encore project was 1440x1080 and there was no need to transcode for a BD disc.  I could not get to any setting quick enough to make it stop.  On raw 1440x1080 footage Encore left it alone.  But for AME rendered 1440x1080 footage it immediately wanted to transcode it to 1920x1080 upon import.  Who knows why.  I had to use Encore CS5 in order to create my menus (it left the AME CS6-rendered video alone) and burn an image and then disc.

     

    Anyone, hope the above helps someone out!

     

    BJBBJB1

     
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