Questions about HDTV MPEG2 encoding

[dsb]

i'm sure i've read that blu ray and hi def dvd will store images in a 1080p 24frame format for movies - even if most players will not output the image in this format.

[Stephen Neal]

Originally Posted by dsb

i'm sure i've read that blu ray and hi def dvd will store images in a 1080p 24frame format for movies - even if most players will not output the image in this format.

Yes - I've read this as well. It will be interesting to see if the on-disc recording is full resolution 24p, with the player adding filtering for interlaced outputs, or if it is pre-filtered to allow the interlacing process to be simpler.

(There is of course the option that there is no interlace filtering - and an assumption is made that most 1080i fed displays will actually be de-interlacing to progressive...)

[Dutch]

Originally Posted by Stephen Neal

1080/50p and 1080/60p are currently impractical for broadcast production (the bandwith is too high for the standard 1.2Gbps HD-SDI interconnect used for uncompressed connections in the broadcast environment) - and they aren't currently part of any proposed broadcast standard AIUI.

This EBU technical paper may be of interest to you, Stephen.

http://www.ebu.ch/CMSimages/en/tec_t...tcm6-37869.pdf

Steve

[Stephen Neal]

Originally Posted by Dutch

This EBU technical paper may be of interest to you, Stephen.

http://www.ebu.ch/CMSimages/en/tec_t...tcm6-37869.pdf

Steve

Yep - had stumbled across that. Saw a demo of a BBC R&D solution to the 1080/50p via an HD-SDI connection problem at a recent open day. They have developed a low latency (8 lines of delay) mezzanine compression scheme that compresses a 1080/50p signal into a 1080/50i HD-SDI video signal. Even more clever is that the compression is devised in such a way that you get a low quality 1080/50i signal as part of the compression - so can monitor the feed for identification purposes with a regular 1080/50i monitor.

It uses a bit more than 2:1 compression - but does actually deliver a solution that would be compatible with existing routing infrastructure - though peripheral devices like vision mixers and VTRs would require compression and decompression units.

(NB Am I the only one who finds the EBU nomenclature of 1080i25 and 1080p25 misleading? It implies that 1080i25 only provides 25 images a second - whereas, although it runs at 25 frames per second, there are 50 separate fields, all potentially taken independently at 50 different points in the second. I much prefer 1080/50i personally...)