Encode or Transcode

[yamyam]

This might seem like a thick question to most of you but can someone tell me what the difference is between encoding & transcoding, i know what encoding does but need to know what transcoding actually does differently ?

Thanks

[mpucoder]

Transcoding works in the compression domain. What this means is two time consuming steps of the encoding process, one of which is critical to good encodes, are skipped. These are determining the motion vectors (critical), and performing the Discrete Cosine Transform (DCT). Avoiding an Inverse Discrete Cosine Transform (IDCT) and a new DCT also reduces errors, as these are not completely reversable processes.

[mrbass]

http://forum.doom9.org/showthread.php?&threadid=44321

good links to what transcoding is

[yamyam]

Thanks for the info but one more question can transcoding give as good quality as encoding ?

[Yannis]

The thread http://forum.doom9.org/showthread.php?s=&threadid=55844
can give you information towards understanding your question.

In short: yes, it can give very good quality, subject to reasonable compression levels and the use of a tool such as InstantCopy which applies a frame-varying transcoding process.

Try both: e.g. InstantCopy and some (slower) encoding solution such as dvd2dvd-r/CCE (considered as a "1.5-click-solution" by some!

yannis

[bb]

Originally posted by mpucoder
Transcoding works in the compression domain.
Actually "transcoding" means nothing than directly decoding and encoding in another format. Transcoders do not necessarily work in the compressed domain, e.g. BeSweet. That's why these one-click tools are often called "compressed domain transcoders".

So in brief "encoding" means uncompressed to compressed format, whereas "transcoding" means compressed to another compressed format.

bb

[mpucoder]

True, but this was in the context of the one-click programs. "Compressed Domain Transcoding" has been shortened to just "transcoding", while those that decode and encode have come to be known as "encoders".

[Yannis]

Actually, the correct title is not even "Compressed Domain Transcoding", but (perhaps) "2D-Signal Compressed Domain Transcoding"

:D :D :D I love semantics :D :D :D LOL