2019-02-04 23:29 GMT+01:00, Ulf Zibis <[email protected]>: > > Am 04.02.19 um 01:00 schrieb Carl Eugen Hoyos: >> 2019-02-03 21:16 GMT+01:00, Ulf Zibis <[email protected]>: >>> Am 03.02.19 um 21:06 schrieb Carl Zwanzig: >>>> It's a shortening of "Top Field First" (TFF). With interlaced video >>>> you have a choice of whether the top or bottom field (odd numbered >>>> lines/even numbered lines) comes before the other in the digital stream. >>> I know this, but Carl Eugen said, that my video is not interlaced > 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.) > - 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" (As explained before, there is no way for FFmpeg to know if the input it really interlaced or not except for running idet which is not done automatically for performance reasons and which - as you showed - is not always helpful). > 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. > the content and decides to remove it. Carl Eugen stated, that libx264 > makes an interlaced output, if the input is interlaced, so I would > think, it shouldn't change the interlace state, if I understood right. > >> FFmpeg cannot know if the video is interlaced. >> (It was encoded interlaced which is not unusual for mpeg2video) > > 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.) Carl Eugen 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. _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
