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Finetuning of the mimetypes mess, hoping to get into a standards document one day...

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Original commit message from CVS:
Finetuning of the mimetypes mess, hoping to get into a standards document one day...
This commit is contained in:
Ronald S. Bultje 2003-06-06 23:49:25 +00:00
parent fdba81e0fa
commit 475c2857a5
1 changed files with 86 additions and 25 deletions
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111
docs/random/mimetypes
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@ -18,6 +18,12 @@ GstCaps *caps = gst_caps_new("video_mpeg_type",
gst_props_new("width", GST_PROPS_INT(384),
"height", GST_PROPS_INT(288),
NULL));
or using a macro:
GstCaps *caps = GST_CAPS_NEW("video_mpeg_type",
"video/mpeg",
"width", GST_PROPS_INT(384),
"height", GST_PROPS_INT(288)
);
Obviously, mimetypes and their corresponding properties are of major
importance in GStreamer for uniquely identifying media streams.
@ -32,6 +38,9 @@ The samplerate _is_ important for _raw_ audio, so a decoder would need
to retrieve the samplerate from the Ogg/Vorbis stream headers (that are
part of the bytestream) in order to pass it on in the GstCaps that
belongs to the decoded audio ('audio/raw').
However, other plugins *might* want to know such properties, even for
compressed streams. One such example is an AVI muxer, which does want
to know the samplerate of an audio stream, even when it is compressed.
Another problem is that many media types can be defined in multiple ways.
For example, MJPEG video can be defined as video/jpeg, video/mjpeg,
@ -52,43 +61,62 @@ AVI or MPEG (bytestream). They mostly contain of a set of headers that
define the media stream(s) that is packed inside the container and the
media data itself.
Video codecs and audio codecs describe encoded audio or video data.
Examples are MPEG-1 video, DivX ;-) video, MPEG-1 layer 3 (MP3) audio
or Ogg/Vorbis audio. Actually, Ogg is a container format too (for Vorbis
Examples are MPEG-1 video, DivX video, MPEG-1 layer 3 (MP3) audio or
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/x-msvideo
mimetype: video/x-avi
2 - Quicktime (Apple)
mimetype: video/x-quicktime
3 - MPEG (MPEG LA)
mimetype: video/mpeg
properties: 'systemstream' = TRUE (BOOLEAN)
4 - ASF (Microsoft)
mimetype: video/x-asf
5 - WAV (PCM)
mimetype: audio/x-wav
6 - RealMedia (Real)
mimetype: video/realmedia
7 - DV (Digital Video)
mimetype: video/dv
properties: 'systemstream' = TRUE (BOOLEAN)
8 - Ogg
mimetypes: media/ogg
8 - Ogg (Xiph)
mimetype: application/x-ogg
9 - Matroska
mimetype: video/x-mkv
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).
3b) Video codecs
For convenience, the fourcc codes used in the AVI container format will be
listed along with the mimetype and optional properties. All video codecs
share the properties 'width' and 'height', both INT, which define the size
of the frame (in pixels).
listed along with the mimetype and optional properties.
Preface - (optional) properties for all video formats:
'width' = X (INT)
'height' = X (INT)
'pixel_width' and 'pixel_height' = X (2xINT, together aspect ratio)
1a - Raw Video (YUV/YCbCr)
mimetype: video/raw
properties: 'format' = 'XXXX' (fourcc)
known fourccs: YUY2, IYUV/I420, Y41P, etc.
known fourccs: YUY2, I420, Y41P, YVYU, UYVY, etc.
Note: some raw video formats have implicit alignment rules. We should
discuss this more.
discuss this more.
Note: some formats have multiple fourccs (e.g. IYUV/I420 or YUY2/YUYV).
For each of these, we only use one (e.g. I420 and YUY2).
1b - Raw Video (RGB)
mimetype: video/raw
@ -144,72 +172,105 @@ of the frame (in pixels).
properties: 'systemstream' = FALSE (BOOLEAN)
'mpegversion' = 1/2/4 (INT)
known fourccs: MPEG, MPGI
3 - DivX ;-) 3.x, 4.x and 5.x video
3 - DivX 3.x, 4.x and 5.x video
mimetype: video/divx
properties: 'divxversion' = 3/4/5 (INT)
optional properties: 'divxversion' = 3/4/5 (INT)
known fourccs: DIV3, DIV4, DIV5, DIVX, DX50, DIVX, divx
4 - Microsoft MPEG 4.1, 4.2 and 4.3
mimetype: video/x-msmpeg
properties: 'mpegversion' = 41/42/43 (INT)
optional properties: 'mpegversion' = 41/42/43 (INT)
known fourccs: MPG4, MP42, MP43
5 - Motion-JPEG (official and extended)
mimetype: video/jpeg
known fourccs: MJPG (YUY2 MJPEG), JPEG (any), PIXL (Pinnacle/Miro), VIXL
6 - Sorensen (Quicktime - SVQ1/SVQ3)
mimetypes: video/x-svq
properties: 'svqversion' = 1/3 (INT)
7 - H263 and related codecs
mimetype: video/h263
known fourccs: H263, i263, M263, x263, VDOW, VIVO
8 - RealVideo (Real)
mimetype: video/realvideo
9 - Digital Video (DV)
mimetype: video/dv
properties: 'systemstream' = FALSE (BOOLEAN)
known fourccs: DVSD, dvsd
10 - Windows Media Video 1 and 2 (WMV)
mimetype: video/wmv
properties: 'wmvversion' = 1/2 (INT)
11 - XviD
mimetype: video/xvid
known fourccs: xvid, XVID
12 - 3IVX
mimetype: video/3ivx
known fourccs: 3IV1, 3IV2
13 - Ogg/Tarkin
mimetype: video/x-ogg-tarkin
14 - Ogg/Theora
mimetype: video/x-ogg-theora
15 - Huffyuv
13 - Ogg/Tarkin (Xiph)
mimetype: video/x-tarkin
15 - VP3
mimetype: video/vp3
15 - Ogg/Theora (Xiph, VP3-like)
mimetype: video/x-theora
16 - Huffyuv
mimetype: video/x-huffyuv
known fourccs: HFYU
TODO: colorspace identifications for MJPEG? How? Move MPEG4-compatible codecs
over to video/mpeg with a subtype (xvid, divx3, divx4, divx5, iso, ...)?
interlacing?
3c) Audio Codecs
for convenience, the two-byte hexcodes (as are being used for identification
in AVI files) are also given
Preface - (optional) properties for all audio formats:
currently none
1 - Raw Audio
mimetype: audio/raw
properties: 'rate' = X (INT) <- samplerate
'width' = X (INT) <- audio bitsize
'depth' = X (INT) <- same?
'width' = X (INT) <- memory bits per sample
'depth' = X (INT) <- used bits per sample
'law' = 0/1/2 (INT) <- no law (0), alaw (1) or mulaw (2)
'signedness' = X (BOOLEAN)
'channels' = X (INT) <- number of audio channels
'endianness' = 1234/4321 <- endianness of audio stream
2 - MPEG-1 layer 1/2/3 audio
mimetype: audio/mpeg
properties: 'mpegversion' = 1/2/3 (INT)
mimetype: audio/x-mp3
properties: 'layer' = 1/2/3 (INT)
3 - Ogg/Vorbis
mimetype: application/x-ogg
mimetype: audio/vorbis
4 - Windows Media Audio 1 and 2 (WMA)
mimetype: audio/wma
properties: 'wmaversion' = 1/2 (INT)
5 - AC3
mimetype: audio/ac3
6 - FLAC (Free Lossless Audio Codec)
mimetype: audio/x-flac
4 - Status of this document
---------------------------
This document is currently under construction and the types listed in here
are purely imaginary. Don't take this as your starting point (yet).
Not all plugins strictly follow these guidelines yet, but these are the
official types. Plugins not following these specs either use extensions
that should be documented, or are buggy (and should be fixed).
Blame Ronald Bultje <rbultje@ronald.bitfreak.net> aka BBB for any mistakes
in this document.