Eric Pautsch
Forum Replies Created
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Not to confuse things anymore but there is no such thing as 23.98 in the DVD spec…..ONLY 29.97 OR 25 FPS. Remember, DVD is 20 year old technology so things like progressive video weren’t a thought! Also the article is incorrect to say you can squeeze higher bitrates into a encode from which inverse Telecine has been applied. It only throws out duplicate frame whICH saves space not allow you to increase bitrates.
Froam the spec:
A disc has one track (stream) of MPEG-2 constant bit rate (CBR) or variable bit rate (VBR) compressed digital video. A restricted version of MPEG-2 Main Profile at Main Level (MP@ML) is used. SP@ML is also supported. MPEG-1 CBR and VBR video is also allowed. 525/60 (NTSC, 29.97 interlaced frames/sec) and 625/50 (PAL/SECAM, 25 interlaced frames/sec) video display systems are expressly supported. Coded frame rates of 24 fps progressive from film, 25 fps interlaced from PAL video, and 29.97 fps interlaced from NTSC video are typical. MPEG-2 progressive_sequence is not allowed, but interlaced sequences can contain progressive pictures and progressive macroblocks. In the case of 24 fps source, the encoder embeds MPEG-2 repeat_first_field flags into the video stream to make the decoder either perform 2-3 pulldown for 60Hz NTSC displays (actually 59.94Hz) or 2-2 pulldown (with resulting 4% speedup) for 50Hz PAL/SECAM displays. In other words, the player doesn’t “know” what the encoded rate is, it simply follows the MPEG-2 encoder’s instructions to produce the predetermined display rate of 25 fps or 29.97 fps. This is one of the main reasons there are two kinds of discs, one for NTSC and one for PAL. (Very few players convert from PAL to NTSC or NTSC to PAL. See 1.19.)
Because film transfers for NTSC and PAL usually use the same coded picture rate (24 fps) but PAL resolution is higher, the PAL version takes more space on the disc. The raw increase before encoding is 20% (480 to 576), but the final result is closer to 15%, depending on encoder efficiency. This translates to an increase of 600 to 700 megabytes on PAL discs compared to NTSC discs.
It’s interesting to note that even interlaced source video can be rendered as progressive-structured MPEG pictures by a good encoder, with interlaced field-encoded macroblocks used only when needed for motion. Most film sources are encoded at 24 frames per second (the inverse telecine process during encoding removes duplicate 2-3 pulldown fields from the videotape source, and the remaining field pairs, although technically in interlaced form, can be re-interleaved by a progressive player). Most video sources are encoded at 25 or 30 interlaced frames per second. These may be mixed on the same disc, such as an interlaced-source logo followed by a progressive-source movie.
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Probably not anytime soon. I know Larry at Rivergate says coding something like this is so much easier under Cocoa. shouldn’t be much of an issue though since the costs attached to provided this service would easily pay for a new mac mini. 🙂
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Not to stop the disc but you can author in a passcode to get access to the disc. Although it easy to get around, it will stop the casual everyday user:
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I heard there are changes you need to make in the authoring process for ripguard titles. I track titles too so all I can say is you’ll need to set those register values right off the bat before playing the title. You’re using Scenarist?
Also…can you give a hint what Ripguard costs per disc unit…just curious. Seems like such as waste of money but if the client wants to pay…so be it!
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You can say that again! Totally annoying afternoon spent several years ago! Oh! Then there was the time I received a muxing error stating:
“English and English-1 languages must differ”
I missed a deadline because of that one 🙂
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The spec says that Layer 0 must be larger than layer one, so any marker at the beginning of the track which makes layer 0 larger than layer 1. Time to do some math !! 🙂
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You can use tools like DVD shrink to make it a 2g disc but quality will take a severe hit! Having a player launch as you insert a pen drive and sees a TS folder will be an issue depending on the player and how each end user has their system set up. Just tell them how to play the TS folder.
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Only give the replicator your Layer 0 and Layer 1 files – these are your DDP images used to create your glass master. Best to deliver on HDD but you can give them burned discs too – check with them.
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Never use DVDSP to compress your streams. Use Compressor – that’s whats its there for. Personally, with something that short I would use a CBR encode of about 7.0. Compressor’s VBR can be a little iffy sometimes (depending on the footage)