Progressive MPEG-2 Video Hardware Decoding

[SeeMoreDigital]

Where exactly should a "hardware" player look for information regarding whether or not an MPEG-2 video stream is "progressive"?


Cheers

[neuron2]

As always, you have to distinguish the actual content from the encoding thereof. Which are you interested in?

The latter can be obtained from MPEG2 syntax flags. The former must be assessed by eye or using imperfect heuristics on the video data.

[LoRd_MuldeR]

Also why does the "hardware" player have to care? It should forward the video content to the screen as-is, interlaced or progressive.

Only the screen/projector "knows" whether interlaced content needs to be deinterlaced or not (e.g. a LCD screen would need to deinterlace, a CRT screen wouldn't).

[SeeMoreDigital]

As always, you have to distinguish the actual content from the encoding thereof. Which are you interested in?

The latter can be obtained from MPEG2 syntax flags. The former must be assessed by eye or using imperfect heuristics on the video data.The method obtained from the MPEG2 syntax flags....

"ReStream" offers two places to enter "progressive" flagging information. The "Picture Coding Extension" and the "Sequence Extension". The following example shows what ReStream reports for a progressive NTSC source with 3:2 pull-down: -

http://img525.imageshack.us/img525/7114/mpeg2samplentscprogress.png

When should the "Sequence Extensions", "Progressive Sequence" option be used?


Cheers

[neuron2]

Setting it in the sequence extension declares that all the frames in the sequence are progressive, i.e., not a possible mix of progressive and interlace encoded pictures.

Significantly, also, when you set it in the sequence extension, it changes the interpretation of the repeat flags, such that they define frame repeats instead of field repeats.

Here's a common example. Start with 23.976 progressive film. Set progressive_sequence and apply 3:2 frame flagging per spec. You end up with 59.94 progressive with a frame (not field) pattern like this:

AAABBCCCDDEEEFF...

You'll see a lot of 720P film content like that.

[SeeMoreDigital]

Thanks Donald. That all makes sense.

A few days ago I looked at the flags in some of my PAL DVD back-ups and out of the twenty or-so that I looked at, Casino Royale was the only one that had the Sequence Extensions, "Progressive Sequence" option checked.

Would having this option "checked" cause any problems to such progressive PAL sources?


Cheers

[neuron2]

Would having this option "checked" cause any problems to such progressive PAL sources? None that immediately occur to me.

[SeeMoreDigital]

None that immediately occur to me.Thanks...