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  1. I have a h.264 video which I created in Quicktime Player 7. QT7 seems to have used the perian codec plugin while creating the video.

    Only Quicktime Player 7 is capable of playing that video, and that only as long as perian is installed. I tried VLC, VideoSpec and ffmpeg and they all failed. ffmpeg and VLC fail to play it saying "unknown decoder 'CAVC'."

    As Quicktime Player 7 is unsupported starting Catalina, I'd like to losslessly convert that video into a new file. The info panel in QuickTime describes the codec as H.264 (Perian) and ac3 (Perian). Unfortunately, passthrough is greyed out when exporting as mp4.

    So, is there a way to play that file, apart from Quicktime Player 7
    or
    is there a way to losslessly convert the video?

    Thanks for any insight
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  2. Member
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    Originally Posted by Busty View Post
    I have a h.264 video which I created in Quicktime Player 7. QT7 seems to have used the perian codec plugin while creating the video.

    Only Quicktime Player 7 is capable of playing that video, and that only as long as perian is installed. I tried VLC, VideoSpec and ffmpeg and they all failed. ffmpeg and VLC fail to play it saying "unknown decoder 'CAVC'."

    As Quicktime Player 7 is unsupported starting Catalina, I'd like to losslessly convert that video into a new file. The info panel in QuickTime describes the codec as H.264 (Perian) and ac3 (Perian). Unfortunately, passthrough is greyed out when exporting as mp4.

    So, is there a way to play that file, apart from Quicktime Player 7
    or
    is there a way to losslessly convert the video?

    Thanks for any insight
    try ffmpeg -i input.mov -pix_fmt yuv420p output.mov
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  3. Member Cornucopia's Avatar
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    assuming its profile & level is standard (e.g. main@main, high@4.1, etc), h264 is h264. so unless it is non-standard (10bit+, lossless intraframe, mvc, alpha channel), h264-encoded media should be playable by ANY h264 decoder.
    Is it non-standard? check with MediaInfo.

    Assuming it isn't non-standard, my educated guess is that it is using a non-standard fourcc (CAVC??). The most common standard fourcc for h264 is "h264" (also "v264", "x264", "avc1", "jvt3").
    Since this is just an assignment of decoder based on signature, just change the fourcc! I would use a hex editor.

    BTW, QT7 (on Windows & Mac) is SO deprecated, I strongly don't recommend its use except as an intermediary when converting old assets to modern codecs (so they don't become technological orphans). If this experience here was an example of that, I would also say the implementation of h264 present in QT is NOT optimal, so I would have gone a different way (ProRes, uncompressed - converting later to final format using better methods).


    Scott
    Last edited by Cornucopia; 9th Jun 2024 at 15:34.
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  4. thanks for your answers, october262 and Cornucopia, much appreciated.

    @ october262: As ffmpeg cannot open the file (Could not find codec parameters for stream 0 (Video: none (CAVC / 0x43564143), none(bt709), 1920x1080, 26181 kb/s): unknown codec), it also fails in reencoding it.

    @ Cornucopia: Media info doesn't say something about the video being standard or non-standard, However it gives some info under general:
    Video Stream AVC, writing library Apple QuickTime 7.6.6, com.apple.quicktime.software: mkvmerge v5.9.0

    and some under video:
    AVC (High@L4.2) (CABAC / 2 Ref Frames) (1 conformance errors)

    Does this give some hints about how to open it? Is there a hex editor you could recommend for editing the fourcc of the video?
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