Archiving AVCHD Footage - Lossless (further) Compression of m2ts Files at DVinfo.net

Robert M Wright · May 14th, 2009, 10:48 AM

I was just messing around with 7-Zip yesterday, seeing what would happen if I tried to compress various types of (already compressed) video files, like m2t HDV and m2ts AVCHD files.

I don't have an AVCHD camera, so I used a demo version of Edius 5 to export AVCHD encoded files, from some 1080i test footage shot with an HV20.

I found that I could get (lossless) compression up to 73% of original file size with some of the AVCHD m2ts files. That really surprised me. It also struck me, that if approximately 75% or better (of original size) compression could be achieved consistently with AVCHD files, as recorded by an HMC150, the contents recorded onto a 32GB card could be neatly fit onto a single BD-R for archiving the original footage.

Would somebody here, who owns an HMC150, be willing to see what kind of compression they can get with AVCHD files actually recorded from camera?

The settings I used that seem to work best, with 7-Zip, are "Ultra" compression level and "LZMA" compression method, with dictionary size of 64MB and word size of 64.

7-Zip is freeware (a very nice alternative to WINZIP), and can be downloaded here:

Download

Robert M Wright · June 15th, 2009, 12:37 PM

For the few (very few considering the number of views and zero replies!) that might be interested:

I just downloaded one of Austin Meyers' mts AVCHD files, that he shot with a Canon HG10, and tried compressing it. The best I could achieve was 97% of original file size. I'd still like to try this on a some files generated by other cameras (especially the HMC150).

Assuming that other AVCHD cameras would produce files that are equally un-compressable, the question begs - Why does Edius produce AVCHD files that are so compressable? I'm guessing Edius' AVCHD compression is fairly poor quality (likely resulting in significantly sub-optimum image quality at any given bitrate). I may try the latest version of Edius, to see if I get different results.

May 14th, 2009, 10:48 AM	#1
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	Archiving AVCHD Footage - Lossless (further) Compression of m2ts Files I was just messing around with 7-Zip yesterday, seeing what would happen if I tried to compress various types of (already compressed) video files, like m2t HDV and m2ts AVCHD files. I don't have an AVCHD camera, so I used a demo version of Edius 5 to export AVCHD encoded files, from some 1080i test footage shot with an HV20. I found that I could get (lossless) compression up to 73% of original file size with some of the AVCHD m2ts files. That really surprised me. It also struck me, that if approximately 75% or better (of original size) compression could be achieved consistently with AVCHD files, as recorded by an HMC150, the contents recorded onto a 32GB card could be neatly fit onto a single BD-R for archiving the original footage. Would somebody here, who owns an HMC150, be willing to see what kind of compression they can get with AVCHD files actually recorded from camera? The settings I used that seem to work best, with 7-Zip, are "Ultra" compression level and "LZMA" compression method, with dictionary size of 64MB and word size of 64. 7-Zip is freeware (a very nice alternative to WINZIP), and can be downloaded here: Download

June 15th, 2009, 12:37 PM	#2
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	For the few (very few considering the number of views and zero replies!) that might be interested: I just downloaded one of Austin Meyers' mts AVCHD files, that he shot with a Canon HG10, and tried compressing it. The best I could achieve was 97% of original file size. I'd still like to try this on a some files generated by other cameras (especially the HMC150). Assuming that other AVCHD cameras would produce files that are equally un-compressable, the question begs - Why does Edius produce AVCHD files that are so compressable? I'm guessing Edius' AVCHD compression is fairly poor quality (likely resulting in significantly sub-optimum image quality at any given bitrate). I may try the latest version of Edius, to see if I get different results.