How does PiP work physically?

[powersfoss]

As I understand it, we'll soon be getting picture-in-picture coming to our PS3 or standalone blu-ray players when the profile 1.1 firmware updates come to our players. So, the main movie is being read from a file on the BD and at the same time a second PiP file is being read from to display the PiP video. My question is, how does the player physically read from 2 different files on the disc at the same time? Doesn't the laser only hit one spot of the disc?

Someone care to enlighten me? Thanks.

[WickyWoo]

all the data is contained in the video stream and the player sends it to the appropriate decoder. Just like it does now for video and sound

[McBain]

Both video streams are carried in the main transport stream.

http://www.emedialive.com/articles/r...leid=11397#iif

[Manco]

PIP is just an illusion. The film data and the PIP data are encoded right along with each other...just like sound as Wicky pointed out. The firmware in 1.1 players simply makes some decisions about which decoder to send the data stream it's peeling off the disk. The main film data goes to decoder 1 and the PIP data goes to decoder 2. When you push the "PIP" button on the remote you will see the PIP stream show up on your HDTV. Push it again to turn it off. But the laser is still picking up the PIP data throughout the entire playback. It's just up to you whether you want to view it or not.

[haushausman]

Easy. Not one, but two magical elves live inside now.

I'd guess the PiP data is stored on a cache and accessed from there.

[Manco]

Originally Posted by haushausman

I'd guess the PiP data is stored on a cache and accessed from there.

Good question. Not sure how much is cached. My understanding is that PIP is meant to be synchronized with the film. Hence you cannot begin PIP from the beginning when in the middle of the film. Which probably would not make sense anyhow. Thinking about it logically, they only have 256MB to work with in a 1.1 player.

[powersfoss]

Thanks for the info, guys. It's all contained in the video stream. Does this imply then that they must consider the extra bandwidth pip would use, albeit small, when keeping the video stream under the 54 mb/s blu-ray transfer rate? Does that imply the AQ or PQ must a take a small hit to accommodate the extra pip data being streamed?

[dialog_gvf]

Originally Posted by powersfoss

Thanks for the info, guys. It's all contained in the video stream. Does this imply then that they must consider the extra bandwidth pip would use, albeit small, when keeping the video stream under the 54 mb/s blu-ray transfer rate? Does that imply the AQ or PQ must a take a small hit to accommodate the extra pip data being streamed?

Absolutely. The combination of all video and audio and subtitle streams is called the mux (multiplexed data), and that has a maximum of 30.54Mbps on HD DVD and 48Mbps on Blu-ray. The maximum TRANSFER rate for the formats are ~36Mbps for HD DVD and ~54Mbps for Blu-ray.

Secondary video (PiP) on HD DVD is a maximum 6Mbps for MPEG-2 and 4Mbps for VC-1/AVC.

Blu-ray actually allows the secondary to go all the way up to full HD, but obviously compromises in the peak of the main may have to occur since two 40Mbps peaks (the maximum video bit-rate) wouldn't be possible.

Gary

[WriteSimply]

Originally Posted by powersfoss

Thanks for the info, guys. It's all contained in the video stream. Does this imply then that they must consider the extra bandwidth pip would use, albeit small, when keeping the video stream under the 54 mb/s blu-ray transfer rate? Does that imply the AQ or PQ must a take a small hit to accommodate the extra pip data being streamed?

As noted in the insider thread recently, YES to both questions.

The studios would have to be careful in planning which movies will have PiP and which won't. PiP discs won't likely to use MPEG-2 for either primary or secondary video. So it's either AVC or VC-1. Secondary audio would likely to be lossy like Dolby Digital 2.0 for example.


fuad

[Slapper]

Originally Posted by dialog_gvf

Absolutely. The combination of all video and audio and subtitle streams is called the mux (multiplexed data), and that has a maximum of 30.54Mbps on HD DVD and 48Mbps on Blu-ray. The maximum TRANSFER rate for the formats are ~36Mbps for HD DVD and ~54Mbps for Blu-ray.

Secondary video (PiP) on HD DVD is a maximum 6Mbps for MPEG-2 and 4Mbps for VC-1/AVC.

Blu-ray actually allows the secondary to go all the way up to full HD, but obviously compromises in the peak of the main may have to occur since two 40Mbps peaks (the maximum video bit-rate) wouldn't be possible.

Gary

I think it could be done at full HD if there is no cap on the Blu PIP bandwidth (I'm not 100% sure what the spec is for the PIP). They would almost HAVE TO use the VC-1 format as it is the most efficient of the hi-def encoding formats. It probably would not look as good as some of the Blu-rays from Sony/Disney, but it could be the same audio/video quality as Warner Blu-rays (which happen to use VC-1 almost exclusively already).

[Petra_Kalbrain]

Here's a logical question... does the PIP actually NEED to be full HD? Since its presence on the screen will be detrimentally smaller than the actual film image, it could still look amazingly crisp in standard resolution. In fact, that image will be so small compared to the standard DVD resolution today that you could even go as far to say that you could encode it at a smaller resolution than standard DVDs. The only advantage I could see in this HD PIP mentality is that you could switch the PIP to full screen and have the film playing in the PIP window instead. But, honestly? Who wants a screen full of one person talking about a movie while the movie itself is playing? 10 times out of 10 I would leave the PIP extra feature in the small PIP state.

Am I missing some other logic behind dual HD feeds for the PIP concept?

[lch]

^^^

true, but it will be useful for those animated movie where they show you the raw/prep drawing in the pip where you can instantly zoom up one or the other to compare the details.

[Petra_Kalbrain]

Originally Posted by lch

^^^

true, but it will be useful for those animated movie where they show you the raw/prep drawing in the pip where you can instantly zoom up one or the other to compare the details.

True. But thinking of it logically, the release ratio of animation compared to live action is maybe 1 in 50 titles (my best guess). Also, not every animated release would incorporate that SPECIFIC use of PIP. Does this very sporadic individual scenario merit infringing on source bandwidth? Thereby, infringing on the quality output of the founding material on the disc?

[Frode]

Originally Posted by Petra_Kalbrain

True. But thinking of it logically, the release ratio of animation compared to live action is maybe 1 in 50 titles (my best guess). Also, not every animated release would incorporate that SPECIFIC use of PIP. Does this very sporadic individual scenario merit infringing on source bandwidth? Thereby, infringing on the quality output of the founding material on the disc?

Depends on what you mean by infringing. A HD pipstream for animated storyboards wouldn't need the full bandwidth that the main picture needs to begin with, simply because it's mostly black lines on a white background, and it compresses very well. The extra resolution is useful, but extra BW isn't really needed to maintain it for the PiP. You have to remember that there is no absolutes, and it's up to the studio to decide how the bit bucket gets used.

Animation is also only one example of pip use - storyboards can be used for regular movies as well. Multi-camera footage can be used for things like concerts and adult movies. I'm sure there's other uses out there that no one's thought of yet, particularly if PiP doesn't have to be enabled for the entire movie, but can be used for only parts of it. Effect shot breakdowns, pre-matte/green-screen etc.

[DrinkMore]

Originally Posted by haushausman

Easy. Not one, but two magical elves live inside now.

I'd guess the PiP data is stored on a cache and accessed from there.

I thought it was hamsters?

[Hussla]

I'm one of those people who think that PiP is a bit of a gimmick and waste of time.

I remember Ghostbusters on DVD when it had the option to have the outline of the directors and actors on screen (like in mystery science theatre) whilst they were giving commentary, it was cool for about 1min then it got annoying and distracting. I'd just prefer to have the voice over commentary and watch the movie.

[Anthony P]

As I understand it, we'll soon be getting picture-in-picture coming to our PS3 or standalone blu-ray players when the profile 1.1 firmware updates come to our players. So, the main movie is being read from a file on the BD and at the same time a second PiP file is being read from to display the PiP video. My question is, how does the player physically read from 2 different files on the disc at the same time? Doesn't the laser only hit one spot of the disc?

Someone care to enlighten me? Thanks.

what you need to realize is that this is nothing new.

Think of it as a shuffled deck of cards, the first card is taken from the top (read in) it is a club, so it is put in the club pile, the second one is a spade so put in a spade pile the next one is a heart so put in the discard pile (you don't care about hearts) the next one is club, diamond, spade, heart, heart, spade, club...... in the end you have a pile of clubs diamonds, spades and hearts. You are not looking at all four cards at the same time, but they are linear and mixed up so that each card comes out at the right time.

So now let's move back to movies. The stream will have main video, PiP video, Language1, lang2, lang3.... , sub1, sub2.... all ogf these are muxed (shuffled) together so that each shows up as needed. Then most are not used (discard pile) while the rest are eventualy fed as needed to the appropriate decoder (video1 to main video, PiP to secondary decoder, language used to the audio decoder....)