Transcoding (no video)

Shredster · Post by **Shredster** » 14 Jan 2006 07:28

Can someone breifly if all possible, explain transcoding to me? I mean, what is the computer doing when its transcoding? Burning takes barely any time at all, but transcoding seems to take forever! I'm just curious, so I know what's happening when its transcoding. Thanks.

akalazou · Post by **akalazou** » 15 Jan 2006 13:20

if you want to burn a dvd, and the video format isnt compatible, the programm will transcode it, so, you have to choose the way you want to transcode it to be compatible. 1 or 2 pass, and other shits that i dont understand yet. an example:

you got a .mov and you want to burn it on a dvd, so since you need to have ampeg2 to be able to burn it, the programm will do it for you and it has to take frame by frame, thats the reason that it takes so long. 30 frames / second ....

i hope i answered your question

CIC flurry · Post by **CIC flurry** » 15 Jan 2006 14:35

There is lots of data in a video file. Copying it just reads it and writes it. I don't know exactly what transcoding does, but I always felt like it looks at all the data per frame and changes it. Basically changing and writing data takes longer than reading and writing data.

I'm not sure of all the changin being done, but the bitrate and size of the file I think are changed.

jerkki · Post by **jerkki** » 16 Jan 2006 03:43

Hi

I guess you are meaning encoding (transcoding is usually the term for changing video format from PAL (european stantard) to NTSC (american stantard) or vice versa).
Raw video files are extremely big if you are editing DV or even HD material. Engineers have developed different methods, called codecs, to pack the data of video file in a smaller size without losing quality. This is called encoding and it is a common operation if you are distibuting your videos in the net or on dvd.
Encoding takes lots of processing power because it analyzes all the frames and changes between every (desired) frame. I don't know the exact method because it is very complex. So if you just burn your videos on a disk in raw format, it goes faster but takes a lot more space. Encoding takes more time but reduces the size and you can fit a lot more (4-10 times more without losing much quality) video on one disk.

There are many good codecs available. Here are a few examples:
-Xvid (mpeg4-based open source codec, takes some time to learn the tweaks but once you do, it might be the best)
-DivX (mpeg4-based commercial codec, about the same quality as Xvid)
-Windows media video (Microsoft's codec, easy to use and decent quality. Mac users don't like this codec and it reduces a lot of color depth of the video file)
-Quicktime video format (Mac-system based codec, used widely by professional in the movie and video industry. About the same quality as Xvid)
-MPEG2 (universal codec used in DVDs, quite good and easy to use)
-MPEG1 (universal codec used in internet distributed videos and sometimes on dvd. This codec works on any computer regardless of operating system)

Hope this helps