PVR: Difference between revisions

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PowerVR is a division of Imagination Technologies (formerly VideoLogic) that develops hardware and software for 2D and 3D rendering, and more.
PowerVR is a division of Imagination Technologies (formerly VideoLogic) that develops hardware and software for 2D and 3D rendering, and more.
 
== Features ==
== Features ==


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==== Pixel Format ====
==== Pixel Format ====
If the most significant 4 bytes contain a value, the full 8 bytes are used to determine the pixel format. <br />
The least significant 4 bytes contain the channel order, each byte containing a single character, or a null character if there are fewer than four channels, e.g., {‘r’, ‘g’, ‘b’, ‘a’} or {‘r’, ‘g’, ‘b’, ‘\0’}. <br />
The most significant 4 bytes state the bit rate for each channel in the same order, each byte containing a single 8bit unsigned integer value, or zero if there are fewer than four channels, e.g., {8, 8, 8, 8} or {5, 6, 5, 0}.


<pre>
If the most significant 4 bytes contain a value, the full 8 bytes are used to determine the pixel format. 
The least significant 4 bytes contain the channel order, each byte containing a single character, or a null character
if there are fewer than four channels, e.g., {‘r’, ‘g’, ‘b’, ‘a’} or {‘r’, ‘g’, ‘b’, ‘\0’}. 
The most significant 4 bytes state the bit rate for each channel in the same order, each byte containing a single 8bit unsigned integer value,
or zero if there are fewer than four channels, e.g., {8, 8, 8, 8} or {5, 6, 5, 0}.
</pre>


<pre>
Where the most significant 4 bytes have been set to ‘0’ and the least significant 4 bytes will contain a 32bit unsigned integer value identifying the pixel format
Where the most significant 4 bytes have been set to ‘0’ and the least significant 4 bytes will contain a 32bit unsigned integer value identifying the pixel format
</pre>
 


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==== Channel Type ====
==== Channel Type ====
<pre>
the data type of the colour channels within the texture data.  
the data type of the colour channels within the texture data.  
</pre>


{| class="wikitable" style="text-align: center;"
{| class="wikitable" style="text-align: center;"

Revision as of 07:49, 28 July 2015


PowerVR Texture Compression files: PVRTC and PVRTC2 are a family of lossy, fixed-rate texture compression formats.

PowerVR is a division of Imagination Technologies (formerly VideoLogic) that develops hardware and software for 2D and 3D rendering, and more.

Features

  • PVRTC supports both opaque (RGB) and translucent (RGBA) textures (unlike other formats such as S3TC that require a dedicated, larger form to support full alpha channels).
  • competitive compression ratios.

File format

The PVR (.pvr) format (Sony uses a custom header) consists of:

Header

Offset (h) Size (h) Example (h) Value (conversion) Notes
PVR header
0x00 0x04 50 56 52 03 "PVR " Version: Contains the version of the PVR header format.
0x04 0x04 00 00 00 00 Flags:
  • 00: No flag has been set
  • 02: Colour values within the texture have been pre-multiplied by the alpha values.
0x08 0x08 72 67 62 61 08 08 08 08 "rgba" Pixel Format: rgba + bit rate per channel
0x10 0x04 00 00 00 00 Colour Space:
  • 0: Texture data is in the Linear RGB colour space
  • 1: Texture data is in the Standard RGB colour space
0x14 0x04 00 00 00 00 0 Channel Type:
0x18 0x08 00 01 00 00 256 Height:
0x1C 0x04 00 01 00 00 256 Width:
0x20 0x04 01 00 00 00 1 Depth:
0x24 0x04 01 00 00 00 1 Num. Surfaces:
0x28 0x04 01 00 00 00 1 Num. Faces:
0x2C 0x04 00 00 00 00 0 Meta Data Size:


Pixel Format

If the most significant 4 bytes contain a value, the full 8 bytes are used to determine the pixel format.
The least significant 4 bytes contain the channel order, each byte containing a single character, or a null character if there are fewer than four channels, e.g., {‘r’, ‘g’, ‘b’, ‘a’} or {‘r’, ‘g’, ‘b’, ‘\0’}.
The most significant 4 bytes state the bit rate for each channel in the same order, each byte containing a single 8bit unsigned integer value, or zero if there are fewer than four channels, e.g., {8, 8, 8, 8} or {5, 6, 5, 0}.


Where the most significant 4 bytes have been set to ‘0’ and the least significant 4 bytes will contain a 32bit unsigned integer value identifying the pixel format


Formats Value
Identifier
PVRTC 2bpp RGB 0
PVRTC 2bpp RGBA 1
PVRTC 4bpp RGB 2
PVRTC 4bpp RGBA 3
PVRTC-II 2bpp 4
PVRTC-II 4bpp 5
ETC1 6
DXT1 7
DXT2 8
DXT3 9
DXT4 10
DXT5 11
BC1 7
BC2 9
BC3 11
BC4 12
BC5 13
BC6 14
BC7 15
UYVY 16
YUY2 17
BW1bpp 18
R9G9B9E5 Shared Exponent 19
RGBG8888 20
GRGB8888 21
ETC2 RGB 22
ETC2 RGBA 23
ETC2 RGB A1 24
EAC R11 25
EAC RG11 26
ASTC_4x4 27
ASTC_5x4 28
ASTC_5x5 29
ASTC_6x5 30
ASTC_6x6 31
ASTC_8x5 32
ASTC_8x6 33
ASTC_8x8 34
ASTC_10x5 35
ASTC_10x6 36
ASTC_10x8 37
ASTC_10x10 38
ASTC_12x10 39
ASTC_12x12 40
ASTC_3x3x3 41
ASTC_4x3x3 42
ASTC_4x4x3 43
ASTC_4x4x4 44
ASTC_5x4x4 45
ASTC_5x5x4 46
ASTC_5x5x5 47
ASTC_6x5x5 48
ASTC_6x6x5 49
ASTC_6x6x6 50

Channel Type

the data type of the colour channels within the texture data.

Data Type Value
Unsigned Byte Normalised 0
Signed Byte Normalised 1
Unsigned Byte 2
Signed Byte 3
Unsigned Short Normalised 4
Signed Short Normalised 5
Unsigned Short 6
Signed Short 7
Unsigned Integer Normalised 8
Signed Integer Normalised 9
Unsigned Integer 10
Signed Integer 11
Float 12

Meta Data Format

...

Texture compression

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