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  1. I've been reading this forum for many years and have found it to be a fantastic resource, but I have not been able to find any information about my current encoding issue.

    I encode my Blu-ray rips using RipBot264 and 99% of them end up with CFR at 23.976fps but every now and then I get an encode that is reported in Media Info as VFR despite the fact that the source is CFR.
    I have tried encoding the same file in Handbrake and selecting the "Contant Frame Rate" option but I get the same result - a VFR file.

    I have tried ripping with MakeMKV and DVDFab but I get the same result.

    I have had issues in the past with audio sync when using VFR so I want to stick with CFR for all my encoding but I cannot seem to get these "problem" rips to encode at 23.976 CFR.

    I assume there is a issue with the source file as I get the same result in both RipBot264 and Handbrake. Can anyone explain what is happening and how I can avoid this problem?
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  2. I'm a MEGA Super Moderator Baldrick's Avatar
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    Can you post the details from a source that causes this? Use mediainfo, open blu-ray m2ts,makemkv mkv and view->text.

    Or maybe it's a mediainfo problem.
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  3. Here is the Media Info data, any idea what is going on here?

    157226957171845452186403690984145537264 (0x7648CF7C27D7C4D410062815032DC8F0)
    C:\Users\*\Documents\*\Video.mkv
    Matroska
    Version 2
    18.8 GiB
    1h 57mn
    Variable
    23.0 Mbps
    Video
    UTC 2015-01-14 08:01:53
    MakeMKV v1.9.0 win(x64-release)
    libmakemkv v1.9.0 (1.3.0/1.4.1) win(x64-release)


    1
    AVC
    Advanced Video Codec
    High@L4.1
    Yes
    4 frames
    M=1, N=12
    V_MPEG4/ISO/AVC
    1h 57mn
    Variable
    21.0 Mbps
    36.2 Mbps
    1 920 pixels
    1 080 pixels
    16:9
    Constant
    23.976 fps
    YUV
    4:2:0
    8 bits
    Progressive
    0.422
    17.2 GiB (91%)
    English
    No
    No
    BT.709
    BT.709
    BT.709


    2
    DTS
    Digital Theater Systems
    A_DTS
    1h 57mn
    Constant
    1 510 Kbps
    6 channels
    Front: L C R, Side: L R, LFE
    48.0 KHz
    24 bits
    Lossy
    1.24 GiB (7%)
    Surround 5.1
    English
    Yes
    No


    3
    PGS
    S_HDMV/PGS
    The same subtitle format used on BDs/HD-DVDs
    English
    No
    No


    en:Chapter 01
    en:Chapter 02
    en:Chapter 03
    en:Chapter 04
    en:Chapter 05
    en:Chapter 06
    en:Chapter 07
    en:Chapter 08
    en:Chapter 09
    en:Chapter 10
    en:Chapter 11
    en:Chapter 12
    en:Chapter 13
    en:Chapter 14
    en:Chapter 15
    en:Chapter 16
    en:Chapter 17
    en:Chapter 18
    en:Chapter 19
    en:Chapter 20
    en:Chapter 21
    en:Chapter 22
    en:Chapter 23
    en:Chapter 24
    en:Chapter 25
    en:Chapter 26
    en:Chapter 27
    en:Chapter 28
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  4. I'm a MEGA Super Moderator Baldrick's Avatar
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    Nope, no idea.
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  5. Originally Posted by duffbeer View Post
    Here is the Media Info data, any idea what is going on here?
    Is the output MP4? If so, I believe it's the way MediaInfo interprets things and it's not always correct. You'll probably find if you open the MP4 with MKVMergeGUI and resave it as an MKV without specifying a frame rate, MediaInfo will report the MKV as constant frame rate.

    If that's the reason (MP4) then it's not uncommon for HandBrake, but Ripbot....... I thought it was an AVISynth based GUI, so inherently constant frame rate? Does it leave behind a log file after an encode?

    The HandBrake story.
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  6. I never encode to MP4 - all my files are MKV. Definitely get a VFR output from both. I'll check for a log file.
    Maybe I could try meGUI.....way too many options for my liking but if it gives me a CFR file then it might be worth it.
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  7. There's an option to tell x264 to be constant frame rate.
    http://mewiki.project357.com/wiki/X264_Settings#force-cfr
    I don't know how you add stuff to the command line for either of those programs

    One method for working with VFR video with programs such as AVISynth is to just encode it as though it's constant frame rate, then use the original timecodes to make it variable again. You could probably do the same in reverse. Extract the video time-codes from the original MKV with MKVCkeaver, then use them for the encoded video when muxing. Although that seems like a lot of work you shouldn't need to be doing. And thinking about it......

    Most muxing programs will set the frame rate to something constant if you specify one. MKVMergeGUI is no different. When you add a video stream for muxing specify the frame rate and after muxing I don't think it can help but be constant. As long as the source and the encode have the same number of frames, I don't know how that could go wrong (audio sync-wise).

    Does Ripbot let you edit the Avisynth scripts it creates? If so, try adding something like this to the end of a script:

    AssumeFPS(24000/1001)

    Or, tell the decoder to output a constant frame rate. Not that it shouldn't but if RipBot indexes MKVs with ffms2, you could try something like this:

    FFVideoSource("E:\video.mkv", fpsnum=24000, fpsden=1001, threads=1)

    It's odd. I really can't think of a reason why it would be happening.
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  8. This is quite annoying and it only happens maybe one out of 50 or 60 encodes. I just noticed that my version FFDShow is dated 2012. Should I update? Could this be the cause?
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  9. Originally Posted by duffbeer View Post
    This is quite annoying and it only happens maybe one out of 50 or 60 encodes. I just noticed that my version FFDShow is dated 2012. Should I update? Could this be the cause?
    I don't know to be honest.

    I'd try checking to see if MediaInfo is misleading you.

    Can you open a video via AVIsynth without too much trouble?

    If so, when you open it, add some frame rate conversion to the script, specifying the frame rate it should be. If the video is VFR, it'll have a different number of frames than if it was CFR. I guess it's possible a VFR and CFR version of the same video could have the same number of frames and the VFR video happens to average out to the same frame rate as the CFR version, but I'm, not sure that'd be too likely.

    So if you open a supposedly VFR video, check the frame count, add some frame rate conversion to the script and check the frame count again, if it hasn't changed then I'm pretty sure they'd both have to be CFR. If the frame count changes, then MediaInfo is correct. As long as it's not due to something silly like the very last frame being dropped, so the second last frame has twice the duration and MediaInfo sees the whole thing as VFR as a result.

    FFMS2 can convert to CFR using the method I posted previously. If the video is VFR, it'll drop/duplicate frames as required to output CFR, hence the frame count changing

    FFVideoSource("E:\video.mkv", fpsnum=24000, fpsden=1001, threads=1)

    Remove the frame rate stuff in blue and check the frame count again. If it didn't change the source is very, very, very likely to be CFR.

    I'm pretty sure the DrectShowSource frame rate conversion works the same way.

    DirectShowSource("E:\video.mkv", fps=23.976, convertfps=true)

    I've used the above method via MeGUI's Script Creator preview countless times. Or you can load a script into MeGUI's video section and use the "re-open video" button to open the preview. The current frame and total frame count should be displayed at the top.

    Or ASVPMod I'm pretty sure it displays frame number, frame count and duration.

    Or open the script with VurtualkDub. It does too.

    Or open a "VFR" MKV with MKVMergeGUI and remux while specifying the frame rate. The result will be the opposite of the above methods. If the MKV is VFR the duration should change. If it's really CFR, it won't.

    Lots of ways to confirm that MediaInfo is telling the truth.
    Last edited by hello_hello; 22nd Jan 2015 at 14:40.
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  10. Originally Posted by hello_hello View Post
    Does Ripbot let you edit the Avisynth scripts it creates? If so, try adding something like this to the end of a script:

    AssumeFPS(24000/1001)
    yes, this is very handy feature in RipBot together with just 100% customizing x264 cmd line, so as for that script, it is in properties, and clicking on "show script",it loads clip something like this, using video variable:
    Code:
    video=DirectShowSource("C:\Untitled.avi",audio=false).ConvertToYV12()
    so one can edit that script to one's liking, for example adding a "dot" at the end of that loading line and then adding simple command right after :
    Code:
    video=DirectShowSource("C:\Untitled.avi",audio=false).ConvertToYV12().AssumeFPS(24000/1001)
    or
    Code:
    video=DirectShowSource("C:\Untitled.avi",audio=false).ConvertToYV12()
    video=video.AssumeFPS(24000/1001)
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