2019-02-21 11:31 GMT+01:00, Ulf Zibis <ulf.zi...@gmx.de>: > > Am 21.02.19 um 01:41 schrieb Carl Eugen Hoyos: >> 2019-02-04 23:29 GMT+01:00, Ulf Zibis <ulf.zi...@gmx.de>: >>> Now I've checked the files with mediainfo: >>> - The vob file is stated as interlaced top first. (I know, this does >>> nothing say about the content, only the flag is evaluated.) >> Doesn't FFmpeg also report this? >> (I believe it should.) > This is what I had asked several times, what the meaning of the string > "top first" on the vob input is. It's just the indication of the flag or > something else?
I believe you are right, I missed / forgot this. I expect it is not shown for all interlaced encoded (x264) streams though. >>> - The transcoded mp4 is stated as progressive. >> Did you specify that you want x264 to encode using >> algorithms for interlaced input material? >> Should be "-flags +idct" > Aha, this appears to be the long awaited answer to my question what you > mean by "encoded interlaced". The x264 encoder has a special > mode/optimization for interlaced material, which should be enabled > manually, as the encoder can't detect the nature of the input material > automatically. Correct. > So I guess, the interlaced flag is set automatically when > "-flags +idct" is used, but never just copied from the input stream. It shouldn't. >>> I don't know, why libx264 doesn't retain the flag, maybe it evaluates >> Again (afair, I already wrote that at some point): >> x264 neither retains nor drops "the flag", it doesn't know >> about the input content, it cannot "evaluate" its content. > > Hm, as mediainfo shows, the flag "interlaced top first" was dropped when > transcoding from vob to mp4, which seems to be the same what > ffmpeg/ffprobe states by the string "top first". It wasn't dropped: It is a property of the input stream (only). >>> I still must admid, that I don't really understand what is meant by >>> "encoded interlaced", is it the same than "has the interlaced flag set"? >>> I see no reason why ffmpeg "cannot know" this flag. >> Of course it knows this flag but since the flag is completely useless >> (for encoding, it may be needed to decode correctly) it cannot be >> used to determine correct settings for encoding. >> >> Allow me to repeat: Except for the intro, the video you provided >> is not interlaced, it has artefacts that may or may not be easier >> to encode when using interlaced encoding. >> (Because of the given quality, this is mostly a moot discussion: >> Just use a low quantiser or keep the "originals", if you are really >> interested in the movie buy a dvd that will beat the quality of >> your recording by far.) > In the meantime I had the chance to phone with the original producer > Moritz Boerner. The film was recorded with 36 mm celluloid and he had > above 250.000 DM, not 20.000 DM to produce the film. So our suspicion after visual inspection was right. > So I buyed the DVD now. Except that it has 3 audio tracks to choose and > the VHS head switching artefacts are missing, it unfortunately has the > equal bad quality than my DVD recorder copy, but even has a worst colour > quality than my copy. The purchased DVD is not a direct telecined copy > from the 36 mm material (disappointing), it seem to be a capture of the > in earlier times provided VHS cassette, but with a better adjusted VHS > player, so the head switching artefacts are missing. Thank you for the info! Maybe you should buy a copy of the film? >> PS: Rethinking, it may be a good idea to add the flags for >> your x264 encoding, I believe the encoder is smart enough >> to decide when / how to use it. I suspect it won't make a >> difference for the native FFmpeg video encoders though. > > Is native vs. x264 encoder something different? The native (FFmpeg-internal) encoders may be a little less sophisticated than x264 (and they don't know a special adaptive interlaced setting because it didn't exist in earlier formats). Carl Eugen _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".