[FFmpeg-user] When to determine frames are progressive or interlaced ?
Carl Eugen Hoyos
cehoyos at ag.or.at
Mon Jan 14 11:23:17 CET 2013
Christian Ebert <blacktrash <at> gmx.net> writes:
> >>> I suspect (and it is what James writes above) that mediainfo
> >>> only tells you if the video was encoded using an encoder
> >>> setting "interlaced" or not. It does not tell anything about
> >>> the actual content.
> Right. mediainfo only inspects metadata, I guess.
"metadata" is not right word imo.
When you encode mpeg2video, you have to decide if you want to
encode "progressive" or "interlaced" - this has not necessarily
anything to do with the content, but with the used algorithms.
Using the right algorithm increases encoding efficiency, using
"interlaced" when encoding progressive material (this is what
all television providers do afaict) is not very expensive,
encoding interlaced input without specifying it to the encoder
can be expensive but is of course possible without visible
quality loss using a small enough quantiser.
> There are still some cases where mediainfo output comes in
> handy, but on the whole it's probably less precise than
> ffprobe or ffmpeg.
In this specific case, it does something else and
I am quite sure it correcly reports the encoding method.
(It simply cannot analyse the actual content)
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