[FFmpeg-user] IMX50 NTSC framesize differs to the SMPTE 356M-2001 Standard - why?

[tim nicholson]

On 15/06/15 09:39, Christoph Gerstbauer wrote:
> 
>>> 1.) Please can you tell me YOUR used syntaxes for IMX30/40/50  for PAL
>>> and NTSC? I want to compare it to mine.
>> Mine look remarkably similar to yours except for the ommission of 'ilme'
>> which makes no sense for an I frame only format.
> 
> Maybe the ffmpeg documentation is not correct?
> "ILME: Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
> Use this option if your input file is interlaced and you want to keep
> the interlaced format for minimum losses. The alternative is to
> deinterlace the input stream with-deinterlace, but deinterlacing
> introduces losses."
> 
>    Our IMX50 source will be always interlaced. But what does ILME have
>    to to with Intra frame encoding (I-frame)? Does ILME only works for

Hmmm. the docs describe 'ilme' twice; in Section 11 (Codec Options) it
simply states:-

‘ilme’   Apply interlaced motion estimation.

For an I frame only format motion estimation is not applicable. So I
would say that ilme has nothing to do with Intra frame encoding.

>    GOP structures in MPEG2 and MPEG4? If yes, this should be explained
>    in the documentation, I think. But it isnt.
> 

Unless the flag performs some other undocumented fuction as well it
ought to be redundant.

-- 
Tim.
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