[NUT-devel] [nut]: r512 - docs/draft-niedermayer-nut-00.xml

[Rich Felker]

On Sun, Oct 28, 2007 at 04:28:22PM +0100, lu_zero wrote:
> Author: lu_zero
> Date: Sun Oct 28 16:28:21 2007
> New Revision: 512
> 
> Log:
> slightly less broken grammar
> 
> 
> Modified:
>    docs/draft-niedermayer-nut-00.xml
> 
> Modified: docs/draft-niedermayer-nut-00.xml
> ==============================================================================
> --- docs/draft-niedermayer-nut-00.xml	(original)
> +++ docs/draft-niedermayer-nut-00.xml	Sun Oct 28 16:28:21 2007
> @@ -101,8 +101,8 @@
>              synchronous 1-in-1-out decoder.
>              </t>
>              <t hangText="frame"> Minimal unit of information that can be
> -            decoded, it is usually holds a video frame, a group of
> -            audio samples or a subtitle line.
> +            decoded, e.g. a video frame, a group of audio samples or a
> +            subtitle line.

It's not always the minimal unit capable of being decoded. For
instance with pcm audio and uncompressed video, it's not a single
sample, and with slice-based video codecs it's not a slice. It's
roughly "the unit of decoding corresponding to a single presentation
moment" but this is also incorrect (audio, interlaced video). Writing
a general definition is just error-prone, imo. The broken-down
definition is, I think:

- noninterlaced video: the unit of data corresponding to exactly one
  moment of presentation; the common notion of a video frame.

- interlaced video: the unit of data corresponding to either one
  moment of presentation, if the encoded format is divisible into
  single-field units, or two moments of presentation implicitly
  separated in time by a codec-defined interval if the encoding uses
  indivisible paired-field storage.

- packetized audio: if the encoding of audio has nontrivial minimal
  units of decoding, the minimal decodable unit

- continuous audio: if the encoding of audio does not have nontrivial
  minimal units of decoding, an implementation- or user-chosen number
  of samples that need not be constant.

- subtitles: any atomic change in the presentation. examples include
  adding or removing one or more lines, change in formatting, clearing
  all subtitles, etc.

These may contain some errors. Feel free to discuss. I just wrote them
off the top of my head.

Rich