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New mimtypes document, going into effect today... For details, see this document, it describes everything and tell sy...

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New mimtypes document, going into effect today... For details, see this document, it describes everything and tell syou what to do and not do. Plugins commit follows in a few seconds (and it's huge)
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Ronald S. Bultje 2003-07-06 20:46:22 +00:00
parent 9e29307e4a
commit f5e3267133
1 changed files with 87 additions and 16 deletions
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103
docs/random/mimetypes
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@ -69,6 +69,7 @@ Ogg/Vorbis audio. Actually, Ogg is a container format too (for Vorbis
audio), but these are usually used in conjunction with each other.
3a) Container formats
---------------------
1 - AVI (Microsoft RIFF/AVI)
mimetype: video/avi
@ -86,12 +87,12 @@ audio), but these are usually used in conjunction with each other.
mimetype: audio/x-wav
6 - RealMedia (Real)
mimetype: audio/x-pn-realaudio
mimetype: video/x-pn-realvideo
properties: 'systemstream' = TRUE (BOOLEAN)
7 - DV (Digital Video)
mimetype: video/dv
mimetype: video/x-dv
properties: 'systemstream' = TRUE (BOOLEAN)
'format' = "PAL"/"NTSC" (STRING)
8 - Ogg (Xiph)
mimetype: application/ogg
@ -102,10 +103,32 @@ audio), but these are usually used in conjunction with each other.
10 - Shockwave (Macromedia)
mimetype: application/x-shockwave-flash
11 - AU audio (Sun)
mimetype: audio/x-au
12 - Mod audio
mimetype: audio/x-mod
13 - FLX video (?)
mimetype: video/x-fli
14 - Monkeyaudio
mimetype: application/x-ape
15 - AIFF audio
mimetype: audio/x-aiff
16 - SID audio
mimetype: audio/x-sid
Please note that we try to keep these mimetypes as similar as possible
to what's used as standard mimetypes in Gnome (Gnome-VFS/Nautilus) and
KDE (Konqueror).
Current problems: there's a very thin line between audio codecs and
audio containers (take mp3 vs. sid, etc.) - this is just a per-case
thing right now and needs to be documented further.
3b) Video codecs
For convenience, the fourcc codes used in the AVI container format will be
listed along with the mimetype and optional properties.
@ -114,6 +137,7 @@ Preface - (optional) properties for all video formats:
'width' = X (INT)
'height' = X (INT)
'pixel_width' and 'pixel_height' = X (2xINT, together aspect ratio)
'framerate' = X (FLOAT)
1 - Raw Video (YUV/YCbCr)
mimetype: video/x-raw-yuv
@ -139,11 +163,14 @@ Preface - (optional) properties for all video formats:
YUV9: planar, Y-U-V order, U/V hor+ver 4x subsampled (YUV-4:1:0, 9bpp)
YVU9: planar, Y-V-U order, U/V hor+ver 4x subsampled (YUV-4:1:0, 9bpp)
Y800: one-plane (Y-only, YUV-4:0:0, 8bpp)
See http://www.fourcc.org/ for more information.
Note: YUV-4:4:4 (both planar and packed, in multiple orders) are missing.
2 - Raw Video (RGB)
2) Raw Video (RGB)
-------------------
mimetype: video/x-raw-rgb
properties: 'endianness' = 1234/4321 (INT) <- endianness
'depth' = 15/16/24 (INT) <- bits per pixel (depth)
@ -205,7 +232,7 @@ Preface - (optional) properties for all video formats:
5 - Microsoft MPEG 4.1, 4.2 and 4.3
mimetype: video/x-msmpeg
optional properties: 'mpegversion' = 41/42/43 (INT)
optional properties: 'msmpegversion' = 41/42/43 (INT)
known fourccs: MPG4, MP42, MP43
6 - Motion-JPEG (official and extended)
@ -222,10 +249,11 @@ Preface - (optional) properties for all video formats:
9 - RealVideo (Real)
mimetype: video/x-pn-realvideo
properties: 'systemstream' = FALSE (BOOLEAN)
known fourccs: RV10, RV20, RV30
10 - Digital Video (DV)
mimetype: video/dv
mimetype: video/x-dv
properties: 'systemstream' = FALSE (BOOLEAN)
known fourccs: DVSD, dvsd
@ -265,11 +293,20 @@ Preface - (optional) properties for all video formats:
mimetype: video/x-indeo
properties: 'indeoversion' = 3 (INT)
TODO: colorspace identifications for MJPEG? How? Move MPEG4-compatible codecs
over to video/mpeg with a subtype (xvid, divx3, divx4, divx5, iso, ...)?
interlacing?
21 - Portable Network Graphics (PNG)
mimetype: video/x-png
TODO: subsampling information for YUV?
TODO: colorspace identifications for MJPEG? How?
TODO: how to distinguish MJPEG-A/B (Quicktime) and lossless JPEG?
TODO: divx4/divx5/xvid/3ivx/mpeg-4 - how to make them overlap? (all
ISO MPEG-4 compatible)
3c) Audio Codecs
----------------
for convenience, the two-byte hexcodes (as are being used for identification
in AVI files) are also given
@ -281,14 +318,15 @@ Preface - (optional) properties for all audio formats:
mimetype: audio/x-raw-int
properties: 'width' = X (INT) <- memory bits per sample
'depth' = X (INT) <- used bits per sample
'signedness' = X (BOOLEAN)
'signed' = X (BOOLEAN)
'endianness' = 1234/4321 (INT)
2 - Raw Audio (floating point format)
mimetype: audio/x-raw-float
properties: 'layout' = "gdouble" and "gfloat" (STRING)
'intercept' = X (FLOAT)
'slope' = X (FLOAT)
properties: 'depth' = X (INT) <- 32=float, 64=double
'endianness' = 1234/4321 (INT) <- use G_BIG/LITTLE_ENDIAN!
'slope' = X (FLOAT, normally 1.0)
'intercept' = X (FLOAT, normally 0.0)
3 - Alaw Raw Audio
mimetype: audio/x-alaw
@ -309,7 +347,7 @@ Preface - (optional) properties for all audio formats:
properties: 'wmaversion' = 1/2 (INT)
8 - AC3
mimetype: audio/x-a52
mimetype: audio/x-ac3
9 - FLAC (Free Lossless Audio Codec)
mimetype: audio/x-flac
@ -331,17 +369,50 @@ Preface - (optional) properties for all audio formats:
example, each sample is 4 bit, and 8 samples are packed
together per channel in the bytestream. For the others,
refer to technical documentation.
We probably want to distinguish these differently, but
I don't know how, yet.
13 - RealAudio (Real)
mimetype: audio/x-pn-realaudio
properties: 'bitrate' = 14400/28800 (INT)
14 - DV Audio
mimetype: audio/dv
mimetype: audio/x-dv
15 - GSM Audio
mimetype: audio/x-gsm
16 - Speex audio
mimetype: audio/x-speex
TODO: adpcm/dv needs confirmation from someone with knowledge...
4 - Status of this document
3d) Plugin Guidelines
---------------------
So, a short bit on what plugins should do. Above, I've stated that
audio properties like "channels" and "rate" or video properties like
"width" and "height" are all optional. This doesn't mean you can
just simply omit them and everything will still work!
An example is the best way to explain all this. AVI needs the width,
height, rate and channels for the AVI header. So if these properties
are missing, avimux cannot work. On the other hand, MPEG doesn't have
such properties in its header and would thus need to parse the stream
in order to find them out; we don't want that either (a plugin does
one job). So normally, mpegdemux and avimux wouldn't allow transcoding.
To solve this problem, there are stream parser elements (such as
mpegaudioparse, ac3parse and mpeg1videoparse).
Conclusions to draw from here: a plugin gives info it can provide as
seen from its own task/job. If it can't, other elements might still
need it and a stream parser needs to be written if it doesn't already
exist.
On properties that can be described by one of these (properties such
as 'width', 'height', 'fps', etc.): they're forbidden and should be
handled using filtered caps.
4) Status of this document
---------------------------
Not all plugins strictly follow these guidelines yet, but these are the
official types. Plugins not following these specs either use extensions