[MPlayer-DOCS] [PATCH] Choosing the video codec

[Guillaume Poirier]

The Wanderer wrote:
> On 12/26/2005 06:02 PM, Guillaume POIRIER wrote:
> 
>> +<sect2 id="menc-feat-dvd-mpeg4-codec">
>> +<title>Choosing the video codec</title>
>> +
>> +<para>
>> +  Choosing the video codec to use depends on several factors, some of
>> +  which widely depend on personal taste and technical constraints.
> 
> 
> As this is phrased, you are saying a verb ("to choose") depends on
> something. To the best of my ability to assess matters at the moment, I
> believe that only a noun can be used with "depend" like that.
> Technically speaking what you mean is something like "Which video
> codec(s) would be good choices to use depends on" et cetera - I would
> not recommend that exact phrasing, because it's awkward enough on its
> own, but it avoids the base problem. Do you see what I mean?

No, I'm afraid I don't.


> In this case I do not think that the double use of "depend" in such
> quick succession is a problem.

Ok, then I'll just leave it as it is now. I don't see how I'd fix this
sentence anyhow without re-writing it.


>> +  <listitem><para>
>> +  <emphasis role="bold">Best quality per fps</emphasis>:
> 
> 
> Per FPS?? What does the frame rate have to do with quality, unless it's
> 'way too low (say, below 20 frames per second)?
> 
> Unless you're referring to "the time it takes to encode" or "the time it
> takes to decode", in which case all I can say is that this is a very
> strange way of talking about matters.

I meant "Best quality per encoding time", so the version I'll commit
will use that form.



>> +  <para>
>> +  If you are after blazing speed you should stick around the default
>> +  settings of the video codec (which doesn't mean you should not
>> experiment
>> +  with some of the options which are mentioned in other sections
>> +  of this guide).
> 
> 
> "stick around" - does that mean "stay in the close vicinity of", as in,
> "do not adjust very far from"? Or do you simply mean "stick with"?

I meant "stay in the close vicinity of the defaults"

BTW, I think that while this advice is appropriate for XviD and x264,
I'd not advise anyone to use lavc's default.

I hope a patch to change lavc's defaults would be ok.



>> +  <listitem><para>
>> +  <emphasis role="bold">Personal taste</emphasis>:
>> +  This is were it gets almost irrational: For the same reason that some
>> +  hanged on to DivX3 for years when newer codecs were already doing
>> wonders,
>> +  some folks will prefer <systemitem class="library">XviD</systemitem>
>> +  or <systemitem class="library">libavcodec</systemitem> MPEG-4 over
>> +  <systemitem class="library">x264</systemitem>.
> 
> 
> "where it gets"
> 
> "hung on to"
> 
> Is that "DivX3", or "DivX 3"?

DivX&nbsp;3
:-P


> I'll note that x264 can, in fact, be undesirable if the video will have
> to be played back on a slower system - not every computer out there is
> remotely powerful enough to play back even reasonably low-resolution
> H.264 at full speed.

Yes, that's right, but I mentionned that earlier. Here I'm making the
supposition that you have the choice to pick any of those codecs.
The DivX 3 case is pretty special as to the best of my knowledge, even
thought the basic options of that codec were pretty limited, there were
a full range of tools to edit/hint the codec to improve quality
significantly. That means that by itself divx3 was pretty limited, but
when used with a lot of care, it was doing wonders (when newer codecs
had a wider range of encoding options, but not the "magic" tools divx3 had).


Guillaume