Reducing Android Image download size.

[KPhillisJr]

I was wondering if it would be possible to change the compression used for the android images away from zip files. This is to greatly reduce the overall file size on download. For example the
16GB image for Android version 5.1.1 released on July 11, 2016 is about 641 Megabytes in it's current zip format. If one changes the file type to 7-zip ( http://7-zip.org/ ) it's possible to further reduce the image to about 487 Megabytes. This is file that is about 30% smaller and should help with lowering bandwidth usage to acquire the image.


Just as a quick note I was using 7zip version 15.14 and I had the following Compression settings...

   

NOTE 1: The compression settings I used means that any system capable of running Microsoft Windows 7 should be able to use 7-zip to decompress the file. The main requirement is to have at least 256MB of ram.

NOTE 2: I used a 8-core system for the compression, however any desktop computer can decompress the file as long as they meet the minimum software requirements.

[tllim]

I was wondering if it would be possible to change the compression used for the android images away from zip files. This is to greatly reduce the overall file size on download. For example the
16GB image for Android version 5.1.1 released on July 11, 2016 is about 641 Megabytes in it's current zip format. If one changes the file type to 7-zip ( http://7-zip.org/ ) it's possible to further reduce the image to about 487 Megabytes. This is file that is about 30% smaller and should help with lowering bandwidth usage to acquire the image.


Just as a quick note I was using 7zip version 15.14 and I had the following Compression settings...



NOTE 1: The compression settings I used means that any system capable of running Microsoft Windows 7 should be able to use 7-zip to decompress the file. The main requirement is to have at least 256MB of ram.

NOTE 2: I used a 8-core system for the compression, however any desktop computer can decompress the file as long as they meet the minimum software requirements.

I actually using 7-zip utility to zip but in normal zip format. I didn't use the 7-zip method due to normal user familiar with zip and can be unziped by all unzip utility.

[KPhillisJr]

I was wondering if it would be possible to change the compression used for the android images away from zip files. This is to greatly reduce the overall file size on download. For example the
16GB image for Android version 5.1.1 released on July 11, 2016 is about 641 Megabytes in it's current zip format. If one changes the file type to 7-zip ( http://7-zip.org/ ) it's possible to further reduce the image to about 487 Megabytes. This is file that is about 30% smaller and should help with lowering bandwidth usage to acquire the image.


Just as a quick note I was using 7zip version 15.14 and I had the following Compression settings...



NOTE 1: The compression settings I used means that any system capable of running Microsoft Windows 7 should be able to use 7-zip to decompress the file. The main requirement is to have at least 256MB of ram.

NOTE 2: I used a 8-core system for the compression, however any desktop computer can decompress the file as long as they meet the minimum software requirements.

I actually using 7-zip utility to zip but in normal zip format. I didn't use the 7-zip method due to normal user familiar with zip and can be unziped by all unzip utility.

Most users who look at setting up a board using the pine64 will most likely be familiar with 7-zip files. In general popular file archiver software titles (see: Wikipedia: Comparison of file archivers ) can handle 7z ( 7-Zip) files without any hassle.


Also on a side note, Zip file format (Wikipedia: Zip (file format)) includes major revisions that break older software titles that supported Zip.

• Version 2.0 (1993) - compression support added. Deflate compression algorithm is added.
  
• Version 2.1 (1996) - Deflate64 compression added
  
• Version 4.5 (2001) - 64-bit zip files introduced.
  
• Version 4.6 (2001) - Bzip2 compression added, but was not published online until version 5.2's appnote.
  
• Version 6.3.0 ( 2006) - LZMA Compression, and PPMd+ compression algorithms added.
  

[tllim]

I was wondering if it would be possible to change the compression used for the android images away from zip files. This is to greatly reduce the overall file size on download. For example the
16GB image for Android version 5.1.1 released on July 11, 2016 is about 641 Megabytes in it's current zip format. If one changes the file type to 7-zip ( http://7-zip.org/ ) it's possible to further reduce the image to about 487 Megabytes. This is file that is about 30% smaller and should help with lowering bandwidth usage to acquire the image.


Just as a quick note I was using 7zip version 15.14 and I had the following Compression settings...



NOTE 1: The compression settings I used means that any system capable of running Microsoft Windows 7 should be able to use 7-zip to decompress the file. The main requirement is to have at least 256MB of ram.

NOTE 2: I used a 8-core system for the compression, however any desktop computer can decompress the file as long as they meet the minimum software requirements.

I actually using 7-zip utility to zip but in normal zip format. I didn't use the 7-zip method due to normal user familiar with zip and can be unziped by all unzip utility.

Most users who look at setting up a board using the pine64 will most likely be familiar with 7-zip files. In general popular file archiver software titles (see: Wikipedia: Comparison of file archivers ) can handle 7z ( 7-Zip) files without any hassle.


Also on a side note, Zip file format (Wikipedia: Zip (file format)) includes major revisions that break older software titles that supported Zip.

• Version 2.0 (1993) - compression support added. Deflate compression algorithm is added.
  
• Version 2.1 (1996) - Deflate64 compression added
  
• Version 4.5 (2001) - 64-bit zip files introduced.
  
• Version 4.6 (2001) - Bzip2 compression added, but was not published online until version 5.2's appnote.
  
• Version 6.3.0 ( 2006) - LZMA Compression, and PPMd+ compression algorithms added.
  

I will check among moderators on their opinions. If majority agree, then I will change to 7zip.

[winstongel]

[quote pid='16317' dateline='1469149999']

• Version 6.3.0 ( 2006) - LZMA Compression, and PPMd+ compression algorithms added.
  

[/quote]

LZMA decoder is simple. But PPMd decoder is complex. LZMA2 is better than LZMA. LZMA2 compression does not replace (supersede) LZMA compression, but LZMA2 is merely an additional "wrapper" around LZMA. With LZMA2, data is split into blocks, but each block is still compressed by "normal" LZMA. Because individula blocks are compressed separately, processing the blocks can be parallelized, which allows for multi-threading. LZMA2 also allows "uncompressed" blocks, to better deal with "already compressed" inputs.