A question about smart rendering and bitrates

[perfection]

I understand that several programs offer smart rendering feature which in simple terms means that the videoand/or audio is 'relayed' rather than 'recoded' and that resuts in a higher quality (at least theoretically) as compared to reprocessing.

I understand that if the imput and output differ in format, color system (PAL/NTSC) frame rate, size and audio properties recoding (read reprocessing) will be required and smart rendering will not be useful and to add the time taken will be comparatively more

My question is if the input video and output profile are identical in format, color system (PAL/NTSC) frame rate, size and audio properties BUT DIFFER ONLY in bitrate (example input mpeg bitrate 8112 Kbps CBR from my capture card and output profile of my editor is 8000 CBR or lets say even VBR) - does such have to be recoded or will it invoke smart rendering ?

Which free software can let me know the exact bitrate and whether VBR or CBR

What is an average birate and a maximum bitrate and will they apply to CBR encoded videos

[guns1inger]

g-spot can tell you if it is VBR or CBR, and what the average bitrate is, amongst many other things.

Average and Max only apply to VBR. Average is the average bitrate you want to maintain, Maximum is the highest bitrate you want used.

Yes, altering bitrate requires, at the very least, re-encoding. It can also be done through a process called Transcoding (DVD Shrink and Rejig do this) which is faster than re-encoding because it works by removing data from the source, not re-encoding the source. It does tend to produce artifacts much sooner than re-encoding, so is best used for smaller reductions.

I have only seen transcoders for mpeg-2 video, not mpeg-4 (Divx/Xvid/AVC)

[jagabo]

Typically, smart rendering programs will ignore your bitrate settings for the parts of the video that aren't reencoded. Only the reencoded sections will be encoded with the specified bitrate.