[FFmpeg-user] Preserving PAL 720x576 resolution

Carl Eugen Hoyos ceffmpeg at gmail.com
Wed Apr 14 01:12:42 EEST 2021

Am Di., 13. Apr. 2021 um 12:48 Uhr schrieb Erik Dobberkau
<erik.dobberkau at gmail.com>:
> > Is your input really 720x576 or is it maybe interlaced content
> > encoded as two separate frames with height 288? This is not
> > yet supported by FFmpeg at all without filter insertion, it is
> > possible that we will never write such atrocities.

> Like it or not, it's a SMPTE standard (doesn't make it "right", but a
> whopping lot of people abide by it, therefore it has relevance in real
> life), which specifies to either wrap every field (i.e. half-frame) into
> its own KLV set (labeled as I1) or both into one (labeled ad I2). The first
> produces a valid Picture Item using a pair of its KLVs, the second only
> needs one, obviously. I've seen I1 more often than I2.
> (There's a third version for "interlaced essence" called F1 which I've not
> yet had to deal with.)

I don't like it, I definitely do not doubt the relevance (I did look into
the issue several times), I just want to point out that once the issue
is fixed (from our pov), it is possible that the requested feature
(remuxing of "interlaced" j2k) will still not work, and never will.

Otoh, it may be possible to only fix the remuxing without supporting
the content;-(
(the worst case, imo)

Carl Eugen

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