Blu-ray framerate

[LeHobbit]

I wanted to know how at which framerate a film is stored on a Blu-ray disc ? I think it's at 24 frames per second. Is that right ? Also what is the resolution of the frame used to store an image on the disc ? Is it always 1920 x 1080 or it depends on the parameters chose by the authorer ?

[stockstar1138]

Originally Posted by LeHobbit

I wanted to know how at which framerate a film is stored on a Blu-ray disc ? I think it's at 24 frames per second. Is that right ? Also what is the resolution of the frame used to store an image on the disc ? Is it always 1920 x 1080 or it depends on the parameters chose by the authorer ?

Yes, blu-ray has a framerate of 24fps.

i have never seen a resolution other than 1920x1080p or 1920x1080i.

[LeHobbit]

Thanks, but can you confirme that a film is PHYSICALLY stored on a disc at 24 fps and that the frame which contains the image of the movie are ALWAYS in 1920 x 1080 whatever the format of the movie is (ie 720p or 480p or 1080p) ?

[McBain]

Some background: http://www.hughsnews.ca/faqs/authori...ifications#4.6

[dialog_gvf]

^^^ Good link. That shows all the supported rates and frame sizes.

[4K2K]

What about content that is in 1080p/50 (or 3840x2160p/50 ) - why isn't Blu-ray going to be updated to handle these important rates?

[Deciazulado]

I actually found it amusing it can encode 480 mpeg-2 video at smoothie bitrates

[LeHobbit]

Originally Posted by McBain

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

Thanks. I already knew this site, but I wanted to know how the film is stored on the disc and not how it is sent to the screen.

[JadedRaverLA]

Originally Posted by LeHobbit

Thanks. I already knew this site, but I wanted to know how the film is stored on the disc and not how it is sent to the screen.

The link posted was for the valid framerates and resolutions for storing video on the disc. "How it is sent to the screen" is a completely different matter that has more to do with your playback device capabilities than the disc spec. (Aside from rules enforcing HDCP, etc).

Currently, almost all discs out there use either 1080p24 or 1080i60 for the main content, though there are a few exceptions, and if you are authoring a title you aren't forced to use those modes.

[LeHobbit]

OK. Thank you now I understand.

[luca_frontino]

Wrong!
The actual framerate is 23.976 fps.
Be careful.

[JadedRaverLA]

Originally Posted by luca_frontino

Wrong!
The actual framerate is 23.976 fps.
Be careful.

What was wrong, excatly?

1080p24 is shorthand for 1920x1080 resolution at 24/1.001 frames per second
1080i60 is shorthand for 1920x1080 resolution at 60/1.001 fields per second

The table linked to (that everyone was talking about) explained that. Writing out 1080p23.9760239609 would be a fairly worthless shorthand, and not really necessary as anyone doing encoding work is using tools that are dealing with the framerates/1.001 anyway.

[LeHobbit]

The video stream is sent to the diffusor in one of the formats specified in the table and this one process and converts it to a desired format. Is that right?

[JadedRaverLA]

Originally Posted by LeHobbit

The video stream is sent to the diffusor in one of the formats specified in the table and this one process and converts it to a desired format. Is that right?

I'm sorry, let me try to clarify. The video stream is stored in one of the formats shown in the table -- it MUST be as nothing else is supported for primary video stream.

The player is responsible for handling the different formats, and outputting in the desired format. That said, most players won't attempt to convert 50i or 60i to 24p, so they will either output 50i/60i or 50p/60p depending on their configuration and deinterlacing capabilities. Also, some players can convert 50i to 60i for display on US HDTVs... but not all do, and the result is far from ideal.

PC-based players generally are able to output in just about any resolution and framerate depending on the display device. Standalone players and the PS3 have their outputs fixed to the standard HDTV resolutions and framerates.

Out of curiosity, are you working on mastering a title, or just interested in the specs and how players handle the conversion?

[LeHobbit]

Thanks for your reply. My question was just for my curiosity and understand what it is done with blu-ray discs.
Just to confirm what I have understood : the film is encoded in one of the format specified in the table. Then, the player output the stream to the TV the best way it can and then the TV do the same thing depending on the settings the user defined. Is that right ? By the way, did you have some good articles that talk about conversion between frame rates ? Thanks.

[swifty7]

can the ps3 convert 50p/i to 60/p/i?

[Stephan.klose]

The movies is normally stored in 1080p / 30 .. But the player can play it back in 24f which is the optimal way of watching a movie

[JadedRaverLA]

Originally Posted by LeHobbit

Thanks for your reply. My question was just for my curiosity and understand what it is done with blu-ray discs.
Just to confirm what I have understood : the film is encoded in one of the format specified in the table. Then, the player output the stream to the TV the best way it can and then the TV do the same thing depending on the settings the user defined. Is that right ? By the way, did you have some good articles that talk about conversion between frame rates ? Thanks.

You've got it. As for format conversion, I think I have some links on my home PC... I'll look when I get home tonight. In general, though, there's only a couple of conversions that are generally done.

To go from 1080p24 to 1080i60 or 1080p60 (most common conversion), the player uses the standard 3:2 pulldown method. You should be able to find LOTS of articles on that process as its been done to convert film to NTSC video for decades.

To go from 1080i60 to 1080p60 the video is processed by the players deinterlacer which recombines the fields in the video stream into a progresive signal. Most players cannot perform other types of framerate conversions (1080i50 to 1080p60, etc) as these require substantially more processing and still generally don't provide for fluid motion. 1080i50 is only really used on discs in PAL countries where the sets can accept a 50 field per second stream.

Originally Posted by swifty7

can the ps3 convert 50p/i to 60/p/i?

Unfortunately not. It undoubtedly has enough processing power, but there are so few 1080i50 titles that SCE feels that there are more important areas to spend their development resources. Also, the judder and smearing caused by the conversion would be annoying.

1080i50 video should be converted to either 1080p24 (ala "Planet Earth") by slowing the video down slightly or 1080i60 by a true framerate conversion by the studio prior to encoding. Generally, slowing it down to 1080p24 works very nicely and doesn't produce motion artifacts, but for concerts where messing with the audio isn't ideal they would need to convert to 1080i60 to preserve the audio speed.

Originally Posted by Stephan.klose

The movies is normally stored in 1080p / 30 .. But the player can play it back in 24f which is the optimal way of watching a movie

Huh?

Actually, 1080p30 is not even a valid storage format on Blu-ray (which is somewhat disappointing). Video shot in that format has to be stored in 1080i60 and hope that the player or TV can recombine the fields correctly. Film and video shot in 1080p24 is stored in that formatm but is easily converted to 1080i60 or 1080p60 using 3:2 pulldown if necessary.

[LeHobbit]

Thank you so much JadedRaverLA for your answer. THe only I want to know is how a famerate of 60i for example is "downconverted" to 24p.

[LeHobbit]

Originally Posted by LeHobbit

Thank you so much JadedRaverLA for your answer. THe only I want to know is how a famerate of 60i for example is "downconverted" to 24p.

I had new questions :

1) What equipement deinterlace the stream ? The TV, the player or one of both ?
2) Does anamorphic also work with Blu-ray ?
3) If a movie is letterboxed or pillarboxed, is it done directly in the encoded stream or it is the player or even the TV that do the job ?