[MPlayer-users] Re: x264 vs xvid

[Dark Shadow]

Thanks, I will try the psnr-video.sh script.

On 11/27/05, Matthias Wieser <mwieser at gmx.de> wrote:
> Am Sonntag, 27. November 2005 04:53 schrieb Dark Shadow:
> > I have heard that the h264 codec is supposed to be better then regular
> > mpeg4 like xvid and was wondering how much smaller would a x264 video
> > would be to get the exact same quality as those 42min 350mb xvid tv
> > shows that could be downloaded off the internet plus compared to a dvd
> > compliant mpeg2 file with say a 2 pass 3000 bitrate.
> >
> > I am not good enough to do the tests and get decent results which is
> > why I am asking.
>
> In the TOOLS directory of mplayer there is a script named psnr-video.sh.
>
> You can use it do compare different reencoded videos to the original
> video. It outputs a PSNR value which describes the mathematical
> differences between the original frames and the recompressed frames. A
> high PSNR means good quality. You should use short test videos because
> this script needs much temporary disk space.
>
> What you could do is:
> 1. Recompress a short test video with xvid (and your standard encoding
>    options).
> 2. Calculate the PSNR between the original and the xvid file (maybe add
>    "-vf pp=de" to the psnr-video.sh options if you normally use
>    postpocessing during video playback). Write down the PSNR value.
> 3. Now recompress the test video with x264 and calculate the PSNR between
>    original and the x264 file. Compare the x264 PSNR to the xvid
>    PSNR. Adjust the x264 bitrate and reencode new x264 files until the
>    x264 PSNR matches the xvid PSNR.
> 4. Compare the filesizes of the xvid file and the x264 file which has the
>    same PSNR as the xvid file.
>
> Regards,
>   Matthias
>
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