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