Best quality to size format ?

[vitamine]

Hi all, just got into convert stuff, I just want to know what is the best quality to size format to convert to. Divx??

[jagabo]

h.264

[vitamine]

what's h.264??

[jagabo]

https://www.videohelp.com/glossary?A#AVC

[DarrellS]

How similar is this codec to the Intel I263 codec. This was my favorite codec until I discovered DivX 3.11 a few years back. XviD is now my compression of choice.
Is this codec made by Intel and is it based off of the old I263 ?

[jagabo]

h.264 can compress about twice as well as MPEG 4 (Divx/Xvid).

[celtic_druid]

AVC is MPEG-4 Part 10, XviD is MPEG-4 Part 2.
You can read about H.263, H.264, MPEG-4, etc. at wikipedia if you are interested.
http://en.wikipedia.org/wiki/H.263
http://en.wikipedia.org/wiki/MPEG-4

[waisky]

Say I have a 1 hour movie and I want to encode it into AVI with xvid codec (doesn't matter xvid or h.264).

How could I find out the right bitrate to use in order to result the best quality ?

The right bitrate means I would not over use bitrate so it ends up become the waste of file size.

please advise. thanks.

[VidGuy]

If you're more concerned about quality than size, most codecs have a "constant quality" or "constant quantization" mode.

For instance - if quality is important to me on XVid, I use constant quality with a quant value of 2 or 2.5...

I believe for x.264 (the "free" version), you use values around 18-26....

You could also grab Gordian Knot - it has a "test" mode that will give you a rough estimate of how big the file has to be for a given quality....

[waisky]

thanks for reply.

Just to confirm with you before I try out Gordian Knot.

I have a movie encoded in x.264 at 1280x720 resolution at size 4.2GB. I would like to re-encode it into xvid at the same resolution and same quality.

I found out SUPER can do the job for me. SUPER can keep the same resolution, same aspect ratio and same frame rate. But the thing is I do not know what is the best bitrate to use for the conversion.

If I insist to use SUPER for the conversion, is that any "calculator" I can use to find out the right bitrate ?

If not, can Gordian Knot support x.264 to xvid conversion ?

thanks again.

[VidGuy]

GK can convert from any AVI to xvid/divx/x.264.

You can always just use the GK quality estimation to determine the right size, then use some other program like SUPER to actually do the conversion (although GK will do the conversion just fine).

GK is a free tool, so there's no cost to give it a shot.

[jagabo]

I have a movie encoded in x.264 at 1280x720 resolution at size 4.2GB. I would like to re-encode it into xvid at the same resolution and same quality.

As VidGuy suggested, if you don't need a file of a particular size, forget bitrate and use constant quality. Set Xvid to single pass quantizer mode and set the quantizer value to 2. That will look very close to the original. At 3 you will see macroblocks if you look closely at still frames but it won't be noticeable at normal playback speeds.

Note: going from x.264 to Xvid will make the file much larger at the same quality.

[celtic_druid]

You would hope that the original x264 stream is not in an avi container though. AVC really has no place in avi and definatly VfW is not suitable for AVC encoding. For that reason I wouldn't recommend GK for encoding x264 either.

[waisky]

I would try out Gordian Knot.

thanks all you guys for all the value response, appreciate it very much.

cheers!