Interlaced conversion question

[Turmel, Frederic]

When decoding mpegts interlace H264 or mpeg2 the stream description is always showing interlace-mode=mixed  (interlace-mode\=\(string\)mixed\) . The question is how can we convert this mixed stream to interleaved interlaced frame?

Usage example is feeding a decklink card to output video. The decklink requires interleaved Interlace frame. I may be missing something so I prefer to ask first. I could submit a Bugzilla with sample input source but maybe it not a bug but a new feature?

I believe that libAV output interleaved interlace frame but I could be wrong. If that's the case, why report mixed? 

I have been talking to slomo in IRC but I figure a bigger audience might be better.

Thanks in advance

/GstPipeline:pipeline0/GstQueue:queue2.GstPad:sink: caps = "video/x-raw\,\ format\=\(string\)I420\,\ width\=\(int\)1920\,\ height\=\(int\)1080\,\ pixel-aspect-ratio\=\(fraction\)1/1\,\ interlace-mode\=\(string\)mixed\,\ chroma-site\=\(string\)mpeg2\,\ colorimetry\=\(string\)bt709\,\ framerate\=\(fraction\)30000/1001"