[FFmpeg-user] Preserving PAL 720x576 resolution

[Erik Dobberkau]

> 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.
>
> Carl Eugen
>


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.)

Best regards,
Erik