[FFmpeg-devel] [RFC/PATCH]Interlaced lossless

Peter B. pb at das-werkstatt.com
Sat Jan 26 13:05:51 CET 2013

On 01/26/2013 05:49 AM, Carl Eugen Hoyos wrote:
> Attached patch fixes ticket #2190 for me (if using mov which supports saving 
> interlace information like yuv4mpeg).
> It duplicates some code across decoders, this may indicate that it is not 
> entirely correct - please advise!

This reminds me of a question I've been having on my mind for a long time.
The code in your patch says:

/*we have interlaced material flagged in container */

Which commandline argument is used to tell lossless codecs like FFv1 or Huffyuv whether the material is to be considered progressive or interlaced - and where is it stored: in the container or the codec - or both?

(For lossy I've been using "-flags +ilme+ildct" [1], but according to FFmpeg's documentation, "ilme" is for MPEG-2/4 only [2] and "ildct" applies to DCT [3], which isn't used in e.g. FFv1 or Huffyuv)

I also presume that the compression ratio is affected if e.g. interlaced is encoded progressively - and vice versa.
Is there a way for me to compare this?

Thank you very much,

== References:
[1] http://www.ffmpeg.org/faq.html#Interlaced-video-looks-very-bad-when-encoded-with-ffmpeg_002c-what-is-wrong_003f
[2] http://www.ffmpeg.org/ffmpeg.html#Advanced-Video-Options
[3] http://en.wikipedia.org/wiki/Discrete_cosine_transform

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