compressing mpeg-2 videos (media)

[ZZ-Diego]

Hi,

can someone explain why the compression/pack ratio of media files (especially
with mpeg-2 videos) is so bad in comparison of compressions to other file types like text, sounds and so on? I am looking for a way to compress mpeg-2 videos to lets say 60% of size. Cause neither WinRAR, WinACE are able to do it, i am wondering if this could be achieved in any way?!.....

Theres a backup tool called Ascomp Backup maker which can be used for backing up hdd datas and the output size "can be 2/3" of original size, but thats a real surf-around of doing this and i am more looking after a specialized media compressing software.

So if someone knows of other ways, to compress mpeg-2 (including AC3), please make my day

best regards & thank you
Diego

[futurex]

compressibility of files, including images and text, depends on a couple of things. includes repetition and range.

eg picture containing a recurring pattern (like a chess board) compress much better than pictures of say a busy street. as for range, an image with only 8-bit colour will compress better than full 24-bit. similar idea for text, video etc

compressing video is what mpeg-4 is for. the codec looks for motion between frames. any static areas are recorded only once, into the i frame. the rest of the frames contain only the difference between keyframes, so lots of space is saved. ofcourse other methods are also implemented, even in audio. mp3, among other things, removes frequencies the human ear does not notice, which also saves space. the equivalent is adaptive quantization for video.

short answer: dont expect archive apps to compress video effectively. use mpeg4 asp or avc

[UncasMS]

compressing already compressed material results in larger file size

the best ratio can be achieved using 7-zip