[Ffmpeg-devel] Differences between mencoder and ffmpeg whenencoding using x264

[Robert Swain]

Hello,

On Sunday 19 February 2006 18:29, Luca Abeni wrote:
> Hi Erik,
>
> On Sun, 2006-02-19 at 13:53 +0100, Erik Slagter wrote:
> > I've got this weird problem, it's probably something I overlooked, so
> > I'd appreciate some help.
>
> [...]
>
> > The mencoder command line gives much better
> > quality (visually) using the same bit rate, almost no blockyness, while
> > the ffmpeg output is full of blocks.
>
> I did not compare ffmpeg and mencoder results, but I can confirm that
> encoding video with x264 through libavcodec / ffmpeg often results in a
> lot of blocks, and the quality is not that good (it is quite easy to get
> a better quality - at the same bitrate - with ffmpeg MPEG4)
>
> I suspect libavcodex/x264.c defaults set some strange value in the x264,
> but I've not been able to track it down (I do not know anything about
> x264 and its parameters).

Yet again someone has noted that the x264 defaults in FFmpeg are lacking. This 
is giving a bad impression of x264. :/

My recommendation for anyone using x264 in FFmpeg would be to check the x264 
command line defaults and explicitly specify all parameters to FFmpeg using 
the defaults from the x264 CLI and whatever alterations one may want to make.

Just setting the output codec to x264 and setting a bit rate or other 
mechanism is insufficient and yet so many people do it. People expect the 
defaults to yield good quality such that they can specify a bit rate to 
evaluate the capability of a codec and it's just not the case.

*sighs*

I really should look into this. Maybe we should start a discussion on how to 
tackle this or continue the presets discussion such that this may be resolved 
for all codecs used in FFmpeg? Or at least the ones that require it.

Rob