VideoHelp Forum
+ Reply to Thread
Results 1 to 8 of 8
Thread
  1. Member THRobinson's Avatar
    Join Date: Aug 2009
    Location: Canada
    Search Comp PM
    Once in a while I'll have a video that's a bit big for my taste, like 18GB and I want it to be around 3GB. So I use VidCoder to re-encode it down in size.

    Video quality wise I'm very happy with the results, but, every so often I have issues with the DTS.

    Right now I did a test and when I made a new video file, I converted the DTS track into many tracks... AAC 2.0 @320 and again @160, AC3 2.0 @320, AC3 5.1 @640, and Dolby Pro Logic II @auto... and in the same spot on all tracks where there is a particularly loud/bassy spot the sound crackles/pops (in this case a book being slammed down).

    I played the file in XBMC on my Sony TV, as well as in Windows Media Player using my desktop speakers (same computer running both) and same noise. If I play the original file with the DTS, the same spot, no crackling or popping.

    Not sure if I'm doing something wrong? software or setting issue? hardware issue? Thought maybe a soundcard issue but plasying through WMP would use the onboard sound, and through XBMC would use the audio through the HDMI card (nVidia GTX650Ti OC 2GB). All drivers are up to date.

    Any ideas? or just un-avoidable when downgrading from DTS?
    Quote Quote  
  2. vanished El Heggunte's Avatar
    Join Date: Jun 2009
    Location: Misplaced Childhood
    Search Comp PM
    Right now I did a test and when I made a new video file, I converted the DTS track into many tracks... AAC 2.0 @320 and again @160, AC3 2.0 @320, AC3 5.1 @640, and Dolby Pro Logic II @auto... and in the same spot on all tracks where there is a particularly loud/bassy spot the sound crackles/pops (in this case a book being slammed down).
    In this case, you could try eac3to for the DTS-2-whatever conversions, and only then add the lower-bitrate audio to the reencoded video. By default, eac3to attempts to "fix" the decompressed audio, whenever it finds any glitch which might screw the lossy recompression.
    Quote Quote  
  3. Try MeGUI. You should be able to load the video file into the audio section and re-encode just the audio that way, or if not extract it first. MeGUI also has a HD Streams Extractor under the Tools menu. It can extract and/or convert the audio during the process using eac3to.
    It could be some sort of odd decoding issue, rather than an encoding one.

    Or there's a standalone version of the HD-DVD/Blu-Ray Stream Extractor. It'll also extract/convert audio from files other than HD-DVD/Blu-ray. It requires eac3to.
    Quote Quote  
  4. Member THRobinson's Avatar
    Join Date: Aug 2009
    Location: Canada
    Search Comp PM
    Giving them a try, but, not really finding MeGui/Eac3to to be very user friendly... especially compared to VidCoder... but I 'think' I may have it figured out... not seeing AAC but I do see AC3 and doubt I'd ever hear a difference anyways.

    EDIT - Ok, so, got it done, used MKVMerge to add it in, and the popping is gone, but, I have to crank the volume way way louder than anything else in my collection to get it at the same level...? Not sure what's happening there.
    Last edited by THRobinson; 29th Apr 2014 at 14:07.
    Quote Quote  
  5. When I convert in VidCoder, I never encode Audio
    Just set to Auto Passthrough and audio part will be copy with preserved quality
    because its DTS audio the file will be more only by 300-200mb from AAC encoded version
    Quote Quote  
  6. Member THRobinson's Avatar
    Join Date: Aug 2009
    Location: Canada
    Search Comp PM
    When I convert I change my DTS to AC35.1 @ 640kbps and an AAC Stereo track @320.

    Usually combined its still less than half the size of a DTS track. Plus I have stereo, since ever so often the 5.1 doesn't really work well (special effects super loud, talking super quiet). Just on occasion the DTS won't convert properly with Vidcoder giving me the static/crackle.

    MeGui I finally gave up on... Converted a few times with different codecs, but drops the volume down in half for some reason.
    Quote Quote  
  7. Originally Posted by THRobinson View Post
    MeGui I finally gave up on... Converted a few times with different codecs, but drops the volume down in half for some reason.
    You didn't have the "normalise peaks" option checked in the audio encoder configuration. That'll increase the overall volume until the peaks are at maximum volume. Downmixing to stereo does tend to reduce the volume a fair bit unless you "normalise".

    If it's still quieter than the downmix Vidcoder produces then maybe Vidcoder isn't adjusting the levels to prevent clipping, and maybe that's what causes the crackling you're hearing. I'd be surpised if Vidcoder isn't downmixing correctly, but anything's possible.

    If you're using the HD Streams Extractor, it normally won't drop the volume as much, if at all, but you can normalise the same way by adding -normalize to the options area.

    For AAC encoding I think you need to manually download the NeroAAC encoder and put it in the MeGUI\tools\eac3to folder. There's a checkbox under Options/Settings/External Program Configuration to enable NeroAacEnc once you do.

    Name:  megui2.gif
Views: 82
Size:  22.7 KB

    Name:  hd.gif
Views: 77
Size:  7.0 KB

    If you extract audio and convert to AAC with the HD Streams extractor it automatically re-encodes using variable bitrate encoding and the default NeroAAC quality setting of Q0.5
    MeGUI's AAC encoder configuration lets you select different encoding methods but it defaults to the same VBR quality setting. That's what I use 99% of the time.
    Last edited by hello_hello; 30th Apr 2014 at 01:06.
    Quote Quote  
  8. Whoops..... I forgot..... you're downmixing.....

    To downmix to stereo with the HD Streams Extractor and normalise when extracting you need to add both -downStereo and -normalize to the options section.

    Name:  hd2.gif
Views: 75
Size:  11.9 KB
    Quote Quote