Talk:OggUVS: Difference between revisions
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== Caveats == | |||
* At very low resolutions it's possible to encode a video that has incomplete timing information because more than one frame could fit into an Ogg page. This represents data loss in the case of variable frame rate video (a common case in devices that are limited to such low resolutions). libogg's default limit of 4kB isn't meaningful; the actual limit is ~64kB. Are people really willing to impose a rule that no more than one field can finish within a page? --[[User:Gumboot|Gumboot]] 06:34, 19 Nov 2005 (PST) | * At very low resolutions it's possible to encode a video that has incomplete timing information because more than one frame could fit into an Ogg page. This represents data loss in the case of variable frame rate video (a common case in devices that are limited to such low resolutions). libogg's default limit of 4kB isn't meaningful; the actual limit is ~64kB. Are people really willing to impose a rule that no more than one field can finish within a page? --[[User:Gumboot|Gumboot]] 06:34, 19 Nov 2005 (PST) | ||
== Field rates and timebase == | |||
The combination of field rate and timebase information amounts to only two scalars. The field rate can be expressed as the number of time steps between each frame. If this is imprecise then the timebase should be increased, or it can be specified that the step rate varies between k and k+1. Multiplying the timebase by the Frame Rate Numerator will have all the original precision. --[[User:Gumboot|Gumboot]] 06:44, 19 Nov 2005 (PST) | |||
The distinction between shutter rate and field rate has not been made clear. It is possible, and not uncommon, to issue two fields from the same sample interval separately. It is also possible to have no shutter at all, and for every pixel to be sampled in a different time interval. Be careful to note the common case where the actual shutter is 24Hz, but the effective shutter rate needs to be declared as 25Hz to be consistent with the audio track and the field rate. --[[User:Gumboot|Gumboot]] 07:01, 19 Nov 2005 (PST) | |||
== Will this thing be lossy or lossless? == | |||
It's neither. It's uncompressed and raw. You may consider it lossless if it helps you understand.--Ivo | |||
:Thanks | |||
== zip == | |||
Could zipping (compressing it in a zip archive) provide a meaningful way of compressing OggUVS to relative small files that can be played? | |||
:OggUVS is not for the common user. Rather it is for video editors and cameras. It's not the "FLAC of video".--Ivo | |||
:: I mean the encapsulating ogg file that could be zipped and played to create relatively small playable video's. | |||
:: Because it's also possible in Gimp to transparantly use zip files. | |||
:: Or in windows it's possible to view thumbnails of images in a zip file without uncompressing it first. | |||
:: (Creating a zip file is very easy, the average user can do it.) | |||
:::ZIP compression (also called LZII and flate/deflate) was designed to compress English language text. It works poorly on video data. Also, to display the thumbnails you see in Windows, the operating system decompresses the ZIP file without you asking. Same with GIMP. [[User:Martin.leese|Martin Leese]] 12:31, 26 January 2008 (PST) | |||
Latest revision as of 12:31, 26 January 2008
Caveats
- At very low resolutions it's possible to encode a video that has incomplete timing information because more than one frame could fit into an Ogg page. This represents data loss in the case of variable frame rate video (a common case in devices that are limited to such low resolutions). libogg's default limit of 4kB isn't meaningful; the actual limit is ~64kB. Are people really willing to impose a rule that no more than one field can finish within a page? --Gumboot 06:34, 19 Nov 2005 (PST)
Field rates and timebase
The combination of field rate and timebase information amounts to only two scalars. The field rate can be expressed as the number of time steps between each frame. If this is imprecise then the timebase should be increased, or it can be specified that the step rate varies between k and k+1. Multiplying the timebase by the Frame Rate Numerator will have all the original precision. --Gumboot 06:44, 19 Nov 2005 (PST)
The distinction between shutter rate and field rate has not been made clear. It is possible, and not uncommon, to issue two fields from the same sample interval separately. It is also possible to have no shutter at all, and for every pixel to be sampled in a different time interval. Be careful to note the common case where the actual shutter is 24Hz, but the effective shutter rate needs to be declared as 25Hz to be consistent with the audio track and the field rate. --Gumboot 07:01, 19 Nov 2005 (PST)
Will this thing be lossy or lossless?
It's neither. It's uncompressed and raw. You may consider it lossless if it helps you understand.--Ivo
- Thanks
zip
Could zipping (compressing it in a zip archive) provide a meaningful way of compressing OggUVS to relative small files that can be played?
- OggUVS is not for the common user. Rather it is for video editors and cameras. It's not the "FLAC of video".--Ivo
- I mean the encapsulating ogg file that could be zipped and played to create relatively small playable video's.
- Because it's also possible in Gimp to transparantly use zip files.
- Or in windows it's possible to view thumbnails of images in a zip file without uncompressing it first.
- (Creating a zip file is very easy, the average user can do it.)
- ZIP compression (also called LZII and flate/deflate) was designed to compress English language text. It works poorly on video data. Also, to display the thumbnails you see in Windows, the operating system decompresses the ZIP file without you asking. Same with GIMP. Martin Leese 12:31, 26 January 2008 (PST)