[FFmpeg-user] Detect interlaced video
nickrobbins at yahoo.com
Tue May 13 22:44:26 CEST 2014
> On Tuesday, May 13, 2014 4:31 PM, Clément Bœsch <u at pkh.me> wrote:
> > On Tue, May 13, 2014 at 10:20:34PM +0200, Oliver Fromme wrote:
>> Carl Eugen Hoyos wrote:
>> > Oliver Fromme <oliver <at> fromme.com> writes:
>> > > Actually I had hoped that there is a flag somewhere
>> > > on the DVD, either in the meta data or in the MPEG2
>> > > stream itself, indicating whether a title is
>> > > interlaced or progressive.
>> > The flag tells you if the stream was encoded using
>> > mpeg2video interlaced or mpeg2video progressive, but
>> > to decide whether or mot to deinterlace a video, only
>> > the actual content is relevant: Progressive content
>> > is often encoded as interlaced and it is of course
>> > possible (although unlikely) that interlaced content
>> > is encoded using progressive frames.
>> Ok, thanks for the explanation. So I will just use the
>> idet filter to determine whether deinterlacing is required.
>> By the way, does it hurt to use the yadif filter on frames
>> that are not interlaced?
> While it might be fine for playback, it will probably alter non interlaced
> frame a lot. You might want to use the timeline system of libavfilter to
> enable the filter in some specific time ranges.
> Clément B.
Yadif definitely hurts progressive video if it is done on everything. you can see it on smooth motion in particular.
If I understand correctly,
should turn video that is a mix of 30 frames per second progressive and 30 fps interlaced into 30 fps progressive and 60 fps progressive. I've had mixed success with it. I've looked a little at the code and played with it and I don't see why it shouldn't work, but I wouldn't count on it.
I would also make sure that the content isn't telecined. If you are talking about something like deleted scenes with comentary from a dvd, it is often a mixed of 24fps->30fps telecine and 30fps progressive. On this, in theory,
should produce a mix of 24fps (originally telecined), 30 fps (originally progressive) and 60 fps (originally interlaced) all progressive.
More information about the ffmpeg-user