Transcoding and Encoding in layman terms

[Sifaga]

there are so many things to do with video that still confuses me. Im new to it all and slowly learning.

is there a difference between transcoding ( Is this what DVDShrink does ) to Endcoding ( Does cce do this )


in audio terms i know its not 100% correct but i understand that converting fom WAV to MP3 is a sought of filtering process, bits of the file are discarding, bits that the human ear cant hear. so you get a smaller file.


is transcoding similar to this ?. what bits does it discard ?

or does it do something like what a jpg is to a bitmap .

any info would be appreciated

[holistic]

http://www.afterdawn.com/glossary/terms/transcoding.cfm

All forms of MPEG "audio/video" media use a lossy form of compression. ie: information is discarded .
The information that is discarded has been decided by a bunch of white lab coat , pocket protecter geeks in the form of the CODEC.

As you stated with your *.wav -> *.mp3 anology MPEG2 also discards information that is not perceived by 99.99% of the population. There are of course limitations to this - ie: bitate ,structure - I fames only or IPBBPBB .

...........Am thinking now that 99.99% number could be way off since it seems alot of people think divx is DVD "quality"

][

[Sifaga]

ok so encoding is

reconstructing the content again

and transcoding is it discards things.

to go from 9gig to 4.3 is some heavy duty discarding does it do things like discard every x number of pixels or does it drop whole frames or merges frames

[Solarjetman]

I always thought that encoding is changing the underlying structure of the file to something different (a divx to mpeg), while transcoding is keeping the structure the same but changing only a component (such as changing a PAL film to NTSC)

[ImaWeTodd]

I'll take a stab

With Regard to programs like DVDShrink and CCE

Encoding - To convert into a specific system of communication

Transcoding - To convert from one system of communication into another

Given that, transcoders are encoders and decoders. Encoders are just encoders.

So CCE + a codec is a transcoder. Shrink only does mpeg to mpeg.

So why is DVDShrink so much faster than CCE? Well, for CCE a codec decodes the source and cce re-encodes it from scratch. Because shrink knows what it is working with, it cheats and doesn't have to go thru the whole decode/encode process. It is a compressed domain transcoder. It only looks at some of the info, making assumptions on what is best. But it knows a lot to start, so it can make some really good guesses.

Let's do an analogy:

I ONLY read english (a terrible personal flaw). If I found a great non-english video conversion guide what would I do? I could try to translate all of the words, or I could make assumptions based on the common words/process I do know. The detail route will get me more info, but is it needed info? This most likely depends on how much detail was initially there.

PS: This is opinion. What do I know?

[dphirschler]

https://www.videohelp.com/glossary#Transcoding
https://www.videohelp.com/glossary#Encoding

Doesn't anybody read the glossary?


Darryl

[FOO]

I find this one instructive and not too long.

http://www.bbc.co.uk/rd/pubs/papers/paper_14/paper_14.html

[ImaWeTodd]

https://www.videohelp.com/glossary#Transcoding
https://www.videohelp.com/glossary#Encoding

Doesn't anybody read the glossary?

Normally I'd agree. But in the case of Transcoding and DVDShrink type tools, the Glossary really lacks.

I find this one instructive and not too long.

http://www.bbc.co.uk/rd/pubs/papers/paper_14/paper_14.html

Great Link !! I found those BBC papers to be generally quite good. Might be a good link for the "Links" section. Maybe I'll do some feedback.

Here is a really great one on Transcoding vs Encoding
http://www.bbc.co.uk/rd/pubs/papers/pdffiles/ibc97ptw.pdf