ProRes 422 help

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    • #44121
      AvatarAnonymous
      Inactive

      Over this past summer I worked for a group of producers who shot an independent film on a low budget (a little less than $1,000,000). They shot on high definition, full 1080p quality. Right now I’m assisting one of the producers in his attempts to sell the film for distribution. I’m also editing together the EPK for the project.

      A little while ago we held a screening of the finished film at a large venue for cast/crew/friends/distributors, and we got a lot of comments about how the film looked flat and lifeless. And we were showing it on a fully calibrated deck straight off an HDCAM SR tape. A few people even said it looked like a movie shot for a lot less than what we spent. Up until now we have been blaming the movie’s bad look on the camera and lighting crew and on the color correction. However, recently I took possession of a hard drive containing a copy of the finished, fully rendered Quicktime file from which the SR tape was made, full 5.1 mix and everything. I’ve been using it to source clips for the EPK.

      To some extent the “flat” look is definitely the fault of the DP and coloring, as the sets were definitely overlit and the colorist definitely didn’t have enough time to do much more than a first pass. But after learning more about the codec used for the file (ProRes 422) and after examining this file itself I’m starting to wonder whether
      overcompression is part of the problem with the movie’s visual
      appearance.

      The file has a running time of almost 104 minutes. My understanding of ProRes is that a “regular” quality 1080p movie would be encoded at 145mbs, and a “high” quality movie would be 220mbs. By my calculations that would mean that, had the finished file been rendered at those bit rates, its final size would have come out around either 904 GBs or 1.37 TBs, respectively.

      The actual size of the finished file that I’ve got? A measly 137 GBs. Which would mean the bitrate would be more like 22mbs.

      Are my calculations accurate, or am I way off here? I’ve never worked with ProRes, so can anyone tell me more about the usual bitrates that finished files are encoded in? Are lower bit rates than those I’ve mentioned permissible? Are my suspicions well founded or am I barking up the wrong tree here?

    • #184921
      AvatarRob
      Participant

      You are right, ProRes 422 is 145mbps and ProRes HQ is 220mbps, but your calculations are way off. Are you sure you are not mistaking mbps for MBps. mbps is megabits per second, and MBps is megabytes per second. The difference is that 8 bits = 1 byte, 8mb = 1MB, 8mbps = 1MBps

      Lets do the math as if your 104 minute video is rendered as ProRes (not ProRes HQ)

      104 Minutes = 6240 seconds.

      If 8mbps = 1MBps, then 145mbps = 18.1 MBps. (145 divided by 8 equals 18.125)

      18.1 MBps X 6240 seconds = 112,944MB for your whole video. (or 122.9GB)

      Now, you said your final QT is 137GB, but keep in mind that ProRes is a variable bitrate codec. It will increase its bitrate during fast motion to maintain a high quality image.

      If you ask me, ProRes is not the reason for your image looking flat. ProRes has been adopted by many professionals. Many capture Uncompressed 10-bit video as ProRes because it holds up just as well. I suspect it is the lighting…although I can’t say for sure because I haven’t seen your video. But I’m positive it’s not due to implementing ProRes

    • #184922
      AvatarAnonymous
      Inactive

      Does ProRes 422 always encode with a 145mbps target bit rate? The people that I talked to gave me the impression that ProRes gave you the ability to set quality on a sliding scale, 145mbps was the default but you could set it lower or higher. Which is what I thought may have happened. But if ProRes doesn’t give you those kind of options then yes, it must be the lighting and coloring.

      So just to be clear, it’s reasonable for a 104 minute movie encoded at 145mbps to come out at 137 GBs then?

    • #184923
      AvatarRob
      Participant

      ProRes will encode 1080p/i video at an average bit rate of 145mpbs. 720p and SD will have lower average bit rates.

      You don’t have the option to change the quality on a slider with ProRes. So it’s absolutely reasonable for your 104-minute 1080p video to be 137GB

    • #184924
      AvatarMORUGY
      Participant

      Hi cant be sure i can help but would you givel a little more information, if possible.

      What cameras names and makes used and what were the settings (hard to check back I know)

      Was it filmed on cards/hdrives or tapes

      How was the footage ingestested and into what

      what os system and edit prog used.

      From my limited experiance this problem can go wrong at many different stages not just the edit.

      can you get a small amount of original footage ie re-ingest and check the quality and settings

      I always like to test quality before going ahead with a big edit.

      you can usually tell if lighting is wrong and a good colour correct can help a bit.

      Tanya Morugy Director/editor/ B.A M.A Apple Cert

    • #184925
      AvatarMORUGY
      Participant

      Hi,

      CNF Productions

      You seem to have left this forum, I hope you found a solution to your problem.

      But if you come back I really would like to know if you shot your movie with the Red camera.

      Thanks

      Tanya

    • #184926
      AvatarRob
      Participant

      He states in his original post that they shot 1080p, therefore, I would assume they did not shoot with the Red camera. While the Red certainly is capable of shooting 1080p, why would you if you had the option for 2K or 4K and had enough hard drive space?

      I guess we’ll never know though.

    • #184927
      AvatarMORUGY
      Participant

      Thanks robgrauert,

      I missed the bit where he said shot on 1080p

      and ofcourse Red Raw wouldnt be that.

      The reason I asked is that I have had a number of people with this type of problem when

      shooting with the Red

      Tanya

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