2 Replies Latest reply: May 19, 2014 9:30 AM by DanielFilming RSS

    A question about bitrate.

    DanielFilming Community Member

      Concerning bitrate, what should I chose?

       

      If the video is gaming at 1080p at 30 fps and it will be used for youtube, what bitrate should I use? And more importantly: why? This is one of the few things I still don't understand about video rendering.

       

      It I click on "match source" it tells me target bitrate is 6 and maximum is 8. Usually I encrease that to 30 target and 31 maximum, but the reason I do that is because I just see a high number and assume it's better. I don't know why I landed on 30 either, if I'm picking high numbers, why not 100? That's what I'm asking you, why not 100?

       

      Question 1:

      How can I figure out what bitrate to use and how can I see the difference?

       

      Question 2:

       

      What is the difference between VBR 1 pass and 2 and CBR? What's best and why?

        • 1. Re: A question about bitrate.
          Richard M Knight Community Member

          1  I use a bit rate of 25 for the Blurays I make, the last one I did was very long and I had to drop it to 17, that still looked ok to me. UK Broadcast tv has a delivery spec. of a minimum bitrate of 50 but what is sent to your tv is a lot less.

           

          2  CBR  Constant bit rate- this encodes each frame at the same bit rate regardless of how complex the frame is. This encodes the fastest but produces the largest files.

              VBR   Variable bit rate- this adjusts the bit rate depending on how complex the video frame is, it allows a higher bit rate for complex sections that have lots of detail and movement. Single pass VBR has a guess on the fly when allocating the bitrate, it might not make best use of the bitrate. Two pass VBR looks at the video during the first pass and logs which sections need the highest bit rate and which sections need the least. This log information is then used during the second pass when the file is written.

          • 2. Re: A question about bitrate.
            DanielFilming Community Member

            Thanks a lot, Richard! I would still like some more info on bitrate for the video though. Maybe someone else knows something.