x264 benefit over other source formats other than DVD and Blueray

[Ahmed28]

I see a great benefit to convert from DVD and BLUE RAY formats to x264 mkv, since x264 mkv give best picture without noticeable loss in quality at lower size

But what about other formats, such as SVCD, VCD, divx/xvid avi, mpeg, wmv, rmvb, mov, and etc ? Would converting them all to x264 mkv, will be beneficial as much ?


Thanks

[Guest]

Fix your title to comply with rule 9 ASAP to avoid a strike.

[LoRd_MuldeR]

Re-encoding from one lossy format to another lossy format will unavoidably kill a certain amount of detail. It certainly will not magically create new detail!

SVCD and VCD are already extremely low quality, because of outdated compression (VCD uses MPEG-1), because of low resolution and because of limited bitrate.
Any further re-encoding (using x264 or anything else) can only make it even worse. Better re-extract the movie from the Original-DVD...

For all the other formats you mention, the same applies: Re-encoding can only make the quality worse, it never makes the quality any better. That's for sure.
Unless there's a very good reason, do NOT re-encode your files !!!

[Ahmed28]

@Neuron, I tried to click edit, but the title isn't editable, so sorry.........

@Lord Mulder, thanks very much for the enlightement =)

[Guest]

Hit edit on your first post and then Go Advanced.

[Ahmed28]

@neuron, thanks, I'll edit the titles of my other post =)

@Lord Mulder, if my old svcd movie spanning 2 discs, like cd 1 and cd 2, the movie dat file in cd 1 is 542 megs and the movie dat file in cd 2 is 448 megs, that means to backup this movie unto my HDD, I need 990 megs space, just for "extremely low quality" movie, if I convert and join them into 1 single x264 mkv, I think I can save more HDD space, am I not ?

[CWR03]

But what about other formats, such as SVCD, VCD, divx/xvid avi, mpeg, wmv, rmvb, mov, and etc ? Would converting them all to x264 mkv, will be beneficial as much ?
Your questions cannot be answered objectively. Give it a try and see if the file size savings are a big enough benefit to justify the loss in quality.

[LoRd_MuldeR]

First of all: The filesize is not defined by the video format, but by the bitrate!

So if you re-encode your 990 MB file from SVCD at the same bitrate, it will come out exactly at 990 MB again.
Only if you lower the bitrate, you can produce a smaller file. And this can be done with any video format, you don't need x264 for that.
However x264 is one of the best encoders you can get. So for a given bitrate x264 will squish out as much quality as possible.

Keep in mind that re-encoding always reduces quality. This fact cannot be changed!
Even re-encoding from a 990 MB SVCD file to a 990 MB H.264 file will cause a certain amount of loss. The loss would be small though.
Compressing down from 990 MB to a smaller size will cause even more loss!

So if I you really need to get it smaller than 990 MB, then x264 is the way to go. It will keep the loss as small as possible.
But x264 cannot prevent the loss entirely, because H.264 is lossy per definition (except for the "lossless" mode).

Conclusion: Unless you REALLY need to re-encode, don't do it ;)

[Ahmed28]

@Lord Mulder, wow, thanks a lot for the explanations =)

[DarkZell666]

It depends on how picky about the quality you are : if, for example, you're ready to loose 2% visual quality (the scale is completely arbitrary) but win 20% in filesize, go for it, but quality won't go up by re-encoding alone.

However, a dirty VCD that recieves good deblocking/denoising/sharpening (via avisynth for example) will end up cleaner (and perhaps smaller in filesize) once re-encoded by x264, though this is very dependant upon how one defines "good" cleaning, the x264 settings used, the nature of the source, etc. I'm surprised the answers given are so pessimistic :eek:

I personnally only re-encode if I have to denoise and I'm sure I manage to do proper cleaning at equal or lower filesize, otherwise I don't bother, but more often than not, cleaning+re-encoding gives great results !

As CWR03 suggests, it's trial-and-error, there's no absolute answer :)