[FFmpeg-user] Capture from USB Dazzle: Interlaced or not interlaced. FFV1 level3 vs h264

Andy Furniss adf.lists at gmail.com
Thu Oct 29 18:11:47 CET 2015

Andy Furniss wrote:
> MrNice wrote:
>> To confirm I have an interlaced USB video, I tried
>> ./ffmpeg -debug 1 -f v4l2 -ts mono2abs -channel 1 -video_size
>> 720x576 -pix_fmt yuyv422 -thread_queue_size 512 -i /dev/video0
>> -c:v libx264 -preset slow -qp 0 -flags +ilme+ildct -aspect 4:3
>> -pix_fmt yuv422p
> This doesn't confirm v4l passes interlaced flags as it seems -flags
> +ilme+ildct tells libx264 to encode as interlaced. It seems to
> default to tff - so it's only luck if it works = source was really
> tff.
> I wasn't testing with v4l, it was a yuyv422 interlaced file (in avi
> flagged as progressive).
> for me the output was identical using -flags +ilme+ildct or
> -x264opts tff=1 (used .mp4 to md5sum as mkv never md5sums the same
> due to guid).
> The latter of course allowing easily to change to bff-1 as required,
> though I guess there are many ways in practice.

Hmm, well, ffprobe -show_frames always shows top_field_first=0 for both
mkv and mp4 even if x264 parameters show "interlaced=tff".

mediainfo calls tff/bff OK - but I don't know what that is looking at.

I have to additionally use -vf setfield=tff to get ffprobe to show

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