VideoHelp Forum
+ Reply to Thread
Results 1 to 9 of 9
Thread
  1. Member
    Join Date: Aug 2014
    Location: USA
    Search Comp PM
    Just a quick question regarding bitrate VS file size. I wanted to know if there is a way to tell when you are no longer gaining image quality on your videos and just size. I wanted to backup a dvd of mine on a Dual Layer 8.5gb disk and I thought it would save encoding time and burning time if I didn't have to make it top out at the disks limit. For all I know maybe somewhere between 5-6 gigs could be the stop where I get top quality and if I make it over that size, I gain just size and not quality. Sorry if this doesn't make too much sense but I am trying to explain it as clear as I can. Thanks for the help.
    Quote Quote  
  2. Member
    Join Date: Nov 2003
    Location: West Texas
    Search PM
    When you say you want to backup a dvd, I assume you mean this is already in DVD-video format? DVD-video is almost always made to fit either DVD-5 or DVD-9, unless you have deliberately specified a custom output size. Oversized DVD's are rarely done, and not all authoring programs allow them. Therefore, if you are starting with a DVD-9 there is no reason to compress it down to 5-6gb in size.

    Burning time differences will be relatively insignificant. Encoding time will be non-existent if you are doing a straight backup, you'll just need a bit of time to rip to the hard drive and then to the blank disc. Compression is what will take time, if you insist on making a DVD-9 smaller.

    The only possible reason to compress a DVD-9 down slightly is if you are worried about burning to the full capacity of your DL DVD media. I wouldn't consider this sufficient reason, not when using good media. Use Verbatim brand +R DL DVD's, as they are the only widely available, reliable brand for DL DVD's.
    Quote Quote  
  3. Member
    Join Date: Aug 2014
    Location: USA
    Search Comp PM
    Ok thanks a lot! Does the same thing apply for a Blu Ray rip? I also have an about 6GB Blu Ray rip that I want to backup on a dual layer disk as a AVCHD since I don't have BD-R discs. Should I max out the Dual Layer disc as well? The rip is already in Matroska/AVC format wanted to re-encode of for quality sake if it helps.
    Quote Quote  
  4. I'm a Super Moderator johns0's Avatar
    Join Date: Jun 2002
    Location: canada
    Search Comp PM
    Re-encoding to a higher bitrate never gives you better quality,just author the clip as.
    I think,therefore i am a hamster.
    Quote Quote  
  5. Member
    Join Date: Aug 2014
    Location: USA
    Search Comp PM
    Originally Posted by johns0 View Post
    Re-encoding to a higher bitrate never gives you better quality,just author the clip as.
    OK so I can just tell TsMuxer to output as AVCHD disc right, without any additional encoding?
    Quote Quote  
  6. Member
    Join Date: Nov 2003
    Location: West Texas
    Search PM
    Re-encoding video tends to degrade it slightly. If it is done very well, you may not notice it in playback, but it is always the best policy to do as few encoding steps as possible.

    So, don't re-encode the mkv file unless it is necessary to adjust it to comply with the specifications of AVCHD video. I have made very, very few AVCHD videos, and only as tests, so I am certainly not the best to advise you on them. I believe AVCHDCoder is popular for this, though I would use BD Rebuilder and set it to use strict AVCHD specifications for BD-9 output. BD Rebuilder will be able to import your mkv file directly.

    Edit: tsMuxeR won't be able to adjust anything if the mkv doesn't meet AVCHD specs. The result might work anyway. Depends on your player. If you have AAC audio in the mkv, I seriously doubt it will work properly.
    Quote Quote  
  7. Member Noahtuck's Avatar
    Join Date: Jun 2004
    Location: ®Inside My Avatar™© U.S.
    Search Comp PM
    When do you stop gaining quality?
    Would that be an oxymoron ?

    You don't "gain" quality when re-encoding something that has been encoded down from a larger size by re-encoding again
    and increasing anything, bitrate, resolution or size.

    What you have is what you have, you can't make it better.
    Originally a member since 2001, LONG LIVE TARAN's!!!
    Quote Quote  
  8. I'm a Super Moderator johns0's Avatar
    Join Date: Jun 2002
    Location: canada
    Search Comp PM
    As long as the video is within blu-ray spec it won't need re-encoding,thing with tsmuxer is it won't give you any warnings if the video is out of spec for blu-ray authoring,if the video is something like 1280x544 or 1920x800 then it needs to be re-encoded to 1280x720 or 1920x1080.

    Also if the r-frames are too high(over 5)then the picture will have smearing and lots of artifacts,more on newer blu-ray players(2011+)my ps3 and bdp-s350 plays authored blu-ray with high r-frames(8+) with no issues but my bpp-s380 can't play them properly.
    I think,therefore i am a hamster.
    Quote Quote  
  9. Member
    Join Date: Aug 2014
    Location: USA
    Search Comp PM
    Ok, thanks all I double checked on MediaInfo that all of my videos specs were AVCHD compliant and they were and i used tsmuxer to make it into the folder format and burned it and it worked fine. I'll remember to not re-encode once I already have a compliant video XD Thanks for the help again.
    Quote Quote