Photo CD

From Just Solve the File Format Problem
(Difference between revisions)
Jump to: navigation, search
(→‎External Links)
 
(6 intermediate revisions by 4 users not shown)
Line 8: Line 8:
 
Kodak '''Photo CD''' ('''PCD''') is an image file format that was used by products and services which developed photographs by digitizing them and writing them to a CD.
 
Kodak '''Photo CD''' ('''PCD''') is an image file format that was used by products and services which developed photographs by digitizing them and writing them to a CD.
  
−
Photo CD files combine six different resolution version of the original image into a single compressed file.
+
Photo CD files combine six different resolution versions of the original image into a single compressed file.
  
 
Designed for 35 mm photography, the original Photo CD Master disc can hold about 100 images, or four, 24-exposure rolls of film. The images are stored using the Photo YCC color encoding metric, developed by Kodak, which stores data at multiple levels of resolution in units called IMAGE PAC files.<ref>https://web.archive.org/web/19961227013151/http://www.kodak.com/digitalImaging/aboutPhotoCD/aboutPCD5.shtml</ref>
 
Designed for 35 mm photography, the original Photo CD Master disc can hold about 100 images, or four, 24-exposure rolls of film. The images are stored using the Photo YCC color encoding metric, developed by Kodak, which stores data at multiple levels of resolution in units called IMAGE PAC files.<ref>https://web.archive.org/web/19961227013151/http://www.kodak.com/digitalImaging/aboutPhotoCD/aboutPCD5.shtml</ref>
Line 14: Line 14:
 
== Identification ==
 
== Identification ==
 
The ASCII string "<code>PCD_IPI</code>" appears in the file, usually(?) at offset 2048.
 
The ASCII string "<code>PCD_IPI</code>" appears in the file, usually(?) at offset 2048.
 +
 +
== Structure ==
 +
Main image (called "Base") is located at 0x30000 and is in 512x768 resolution, uncompressed and YUV color space.
 +
List of resolutions:
 +
 +
<pre>
 +
192x128
 +
384x256
 +
768x512
 +
1536x1024
 +
3072x2048
 +
6144x4096
 +
</pre>
 +
First 3 resolutions are not encoded and are used as thumbnails. 1536x1024 image needs to be Huffman decompressed and its elements added to each corresponding pixel of 768x512 image upscaled to 1536x1024.
 +
The same with higher resolutions. 6144x4096 might be stored in a separate file.
  
 
== Converting PCD to other formats ==
 
== Converting PCD to other formats ==
Line 59: Line 74:
 
* http://www.fileformat.info/format/photocd/sample/index.htm (file uses a [[PICT]] wrapper)
 
* http://www.fileformat.info/format/photocd/sample/index.htm (file uses a [[PICT]] wrapper)
 
* [https://archive.org/details/Kodak_PhotoCD_Photo_Sampler_Eastman_Kodak_Company_1991 Kodak PhotoCD Sampler Disc Image]
 
* [https://archive.org/details/Kodak_PhotoCD_Photo_Sampler_Eastman_Kodak_Company_1991 Kodak PhotoCD Sampler Disc Image]
 +
* {{DexvertSamples|image/pcd}}
 +
 +
== Libraries ==
 +
* [https://github.com/Xelitan/PCD-reader-for-Delphi-Lazarus-Free-Pascal PCD unit for Delphi/Lazarus] - library in Pascal
  
 
== Software ==
 
== Software ==
Line 67: Line 86:
 
* [[Wikipedia:Photo CD|Wikipedia article]]
 
* [[Wikipedia:Photo CD|Wikipedia article]]
 
* [http://www.kodak.com/go/photocd Kodak Photo CD web page]
 
* [http://www.kodak.com/go/photocd Kodak Photo CD web page]
 +
* [https://web.archive.org/web/19991013140924/http://kodak.com/US/en/digital/dlc/book2/chapter4/imgpacp1.shtml Kodak Image Pac Learning (archived)]
 
* {{EGFF|photocd|Kodak Photo CD File Format Summary}}, from the [[Encyclopedia of Graphics File Formats]]
 
* {{EGFF|photocd|Kodak Photo CD File Format Summary}}, from the [[Encyclopedia of Graphics File Formats]]
 
* [https://archive.org/details/mac_Graphics_File_Formats_Second_Edition_1996/page/n543/mode/2up Encyclopedia of Graphics File Formats Chapter on PCD]
 
* [https://archive.org/details/mac_Graphics_File_Formats_Second_Edition_1996/page/n543/mode/2up Encyclopedia of Graphics File Formats Chapter on PCD]

Latest revision as of 12:40, 15 March 2025

File Format
Name Photo CD
Ontology
Extension(s) .pcd
PRONOM fmt/211
Released 1992

Kodak Photo CD (PCD) is an image file format that was used by products and services which developed photographs by digitizing them and writing them to a CD.

Photo CD files combine six different resolution versions of the original image into a single compressed file.

Designed for 35 mm photography, the original Photo CD Master disc can hold about 100 images, or four, 24-exposure rolls of film. The images are stored using the Photo YCC color encoding metric, developed by Kodak, which stores data at multiple levels of resolution in units called IMAGE PAC files.[1]

Contents

 [hide] 

[edit] Identification

The ASCII string "PCD_IPI" appears in the file, usually(?) at offset 2048.

[edit] Structure

Main image (called "Base") is located at 0x30000 and is in 512x768 resolution, uncompressed and YUV color space. List of resolutions: 

192x128
384x256
768x512
1536x1024
3072x2048
6144x4096

First 3 resolutions are not encoded and are used as thumbnails. 1536x1024 image needs to be Huffman decompressed and its elements added to each corresponding pixel of 768x512 image upscaled to 1536x1024. The same with higher resolutions. 6144x4096 might be stored in a separate file.

[edit] Converting PCD to other formats

PCD files contain multiple resolutions and have other subtitles that tools must be aware of. This page discusses tool support, and recommends pcdtojpeg over ImageMagick, which had flaws at that time. It seems that later versions of ImageMagick have dealt with the colour blow-out issues.

Note that, when converting PCD files using ImageMagick, you must manually select the resolution layer you want. e.g. 

$ convert BlownJohn.pcd[0] BlownJohn-0.png
$ convert BlownJohn.pcd[1] BlownJohn-1.png
$ convert BlownJohn.pcd[2] BlownJohn-2.png
$ convert BlownJohn.pcd[3] BlownJohn-3.png
$ convert BlownJohn.pcd[4] BlownJohn-4.png
$ convert BlownJohn.pcd[5] BlownJohn-5.png
$ convert BlownJohn.pcd[6] BlownJohn-6.png
$ convert BlownJohn.pcd[7] BlownJohn-7.png
$ convert BlownJohn.pcd[8] BlownJohn-8.png

However, examining the results, we can see that some of these are the same: 

$ ls -l BlownJohn-?.png
     52322  BlownJohn-0.png
     52322  BlownJohn-1.png
    191840  BlownJohn-2.png
    707221  BlownJohn-3.png
   2476659  BlownJohn-4.png
   9668328  BlownJohn-5.png
  28572165  BlownJohn-6.png
  28572165  BlownJohn-7.png
  28572165  BlownJohn-8.png

i.e. (0,1) are identical, as are (6,7,8), with (1) being the lowest resolution and (6) being the highest. This is consistent with the six resolutions that should be present in the PCD. For the highest resolution, use this: 

$ convert BlownJohn.pcd[6] BlownJohn.png

The pcd2html tool may also be useful.

[edit] Sample files

[edit] Libraries

[edit] Software

[edit] External Links

[edit] References

  1. ↑ https://web.archive.org/web/19961227013151/http://www.kodak.com/digitalImaging/aboutPhotoCD/aboutPCD5.shtml
Retrieved from "http://fileformats.archiveteam.org/index.php?title=Photo_CD&oldid=50091"
Personal tools
Namespaces

Variants
Actions
Navigation
Toolbox