suggestions for main/docs/xml/en/encoding-guide.xml
sorry i missed the first couple threads on this, i think its a well written guide and just needs a bit more polishing.
<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
like size, quality, streamability, usability and popularity as well as... (popularity meaning that even if x264 is the greatest current codec, not everyone has the h264 decoding library installed, just like it took a while for everyone to get divx3 and then to get xvid...)
which widely depend on personal taste and technical constraints. </para> <itemizedlist> <listitem><para> <emphasis role="bold">Compression efficiency</emphasis>: It is quite easy to understand that newer-generation codecs are made to yield better picture quality than previous generations.
how about just 'most newer-generation codecs are made to increase quality and compression'
Therefore, you cannot go wrong
therefor, the authors of this guide, and many other people (doom9, others?) suggest you use an mpeg-4 avc codec like...
<footnote id='fn-menc-feat-dvd-mpeg4-codec-cpu'> <para>Be careful, however: Decoding DVD-resolution MPEG-4 AVC videos requires a fast machine (i.e. a Pentium 4 over 1.5Ghz or a Pentium M over 1Ghz). </para></footnote> when choosing MPEG-4 AVC codecs like <systemitem class="library">x264</systemitem> instead of MPEG-4 ASP codecs such as <systemitem class="library">libavcodec</systemitem> MPEG-4 or <systemitem class="library">XviD</systemitem>. (To get a better grasp of what the fundamental differences between MPEG-4 ASP and MPEG-4 AVC are, you would be well advised to read the entry "<ulink url="http://guru.multimedia.cx/?p=10">15 reasons why MPEG4 sucks</ulink>" from Michael Niedermayer's blog.)
imo, that blog post is horribly inefficient at telling the average user the differences between mp4 asp and mp4 avc... the user does not care about the framework of the codec. either a guide showing the difference should be linked to or this part removed. or maybe 'advanced codec developers maybe interested in reading michael ni's opinion on why mpeg4 asp codecs suck'
Likewise, you should get better quality using MPEG-4 ASP instead of MPEG-2 codecs. </para> <para> However, newer codecs which are in heavy development can suffer from bugs which have not yet been noticed and which can ruin an encode. This is simply the tradeoff for using bleeding-edge technology.
bleeding edge? do non-native english people know this word? how about 'newest technology' ?
</para> <para> What is more, beginning to use a new codec requires that you spend some time becoming familiar with its options, so that you know what to adjust to achieve a desired picture quality. </para></listitem>
<listitem><para> <emphasis role="bold">Hardware compatibility</emphasis>: It usually takes a long time for standalone video players to begin to include support for the latest video codecs. As a result, most only support MPEG-2 and MPEG-4 ASP (Beware: Usually, not all MPEG-4 ASP features are supported). Please refer to the technical specs of your player (if they are available), or google around for more information. </para></listitem>
<listitem><para> <emphasis role="bold">Best quality per encoding time</emphasis>: Codecs that have been around for some time (such as <systemitem class="library">libavcodec</systemitem> MPEG-4 and <systemitem class="library">XviD</systemitem>) are usually heavily optimized with all kinds of smart algorithms and SIMD assembly code. That is why they tend to yield the best quality quality per encoding time ratio. However, they may have some very advanced options that, if enabled, will make the encode really slow for marginal gains. </para> <para> If you are after blazing speed you should stick around the default settings of the video codec (which does not mean you should not experiment
double negative. -(which does not mean you should not experiment +(you should still try the other options which are mentioned in other sections
with some of the options which are mentioned in other sections of this guide). </para> <para> You may also consider choosing a codec which can do multi-threaded processing. <systemitem class="library">libavcodec</systemitem> MPEG-4 does allow that, resulting in small speed gains at the price of lower picture quality. <systemitem class="library">XviD</systemitem> has some experimental patches available to boost encoding speed, by about 40-60% in typical cases, with low picture degradation. <systemitem class="library">x264</systemitem> also allows multi-threaded encoding, which currently speeds-up encoding by 15-30% while lowering PSNR by about 0.05dB. </para></listitem>
err, where does using threads affect picture quality? this needs to be rephrased... and where did you get those statistics? 40-60% speedup using what? an smp box? if so, say so..
<listitem><para> <emphasis role="bold">Personal taste</emphasis>: This is where it gets almost irrational: For the same reason that some hung on to DivX 3 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>. </para>
hmm, this makes little sense unless you were around during those divx3 days... how about: Back when the majority of people were using divx3 and newer codecs started emerging, some people chose to stick with divx3. they might have been afraid of change. this meant that they lost out on better quality codecs and got stuck with old divx3 bugs. this is also happening today with libavcodec and xvid vs the newer codecs like x264.
<para> Make your own judgment, and do not always listen to what some people will tell you to do or think: The best codec is the one you master the best,
doesnt this then invalidate the guide? :) how about something like: Make your own judgement, do not take advice from people who swear by one codec. take a few sample clips from raw sources and compare different encoding options/codecs to find one that suits you best.
and the one that looks best to your eyes on your display <footnote id='fn-menc-feat-dvd-mpeg4-codec-playback'> <para>The same encode may not look the same on someone else's monitor or when played back by a different decoder, so future-proof your encodes by playing them back on different setups.</para></footnote>! </para></listitem> </itemizedlist> <para> Please refer to the section <link linkend="menc-feat-selecting-codec">selecting codecs and container formats</link> to get a list of supported codecs. </para> </sect2>
On Sun, Jan 01, 2006 at 11:27:52AM -0500, compn wrote:
<footnote id='fn-menc-feat-dvd-mpeg4-codec-cpu'> <para>Be careful, however: Decoding DVD-resolution MPEG-4 AVC videos requires a fast machine (i.e. a Pentium 4 over 1.5Ghz or a Pentium M over 1Ghz). </para></footnote> when choosing MPEG-4 AVC codecs like <systemitem class="library">x264</systemitem> instead of MPEG-4 ASP codecs such as <systemitem class="library">libavcodec</systemitem> MPEG-4 or <systemitem class="library">XviD</systemitem>. (To get a better grasp of what the fundamental differences between MPEG-4 ASP and MPEG-4 AVC are, you would be well advised to read the entry "<ulink url="http://guru.multimedia.cx/?p=10">15 reasons why MPEG4 sucks</ulink>" from Michael Niedermayer's blog.)
imo, that blog post is horribly inefficient at telling the average user the differences between mp4 asp and mp4 avc... the user does not care about the framework of the codec. either a guide showing the difference should be linked to or this part removed. or maybe 'advanced codec developers maybe interested in reading michael ni's opinion on why mpeg4 asp codecs suck'
I just want to underscore compn's point here. Let's make a list of the stupid things about H.264 - I'm sure some of them would be funnier than Michael's list of MPEG-4 Part 2 follies. I also bet more of them would be relevant to USERS of the codec. Offering that blog post as a reason to use H.264 is pure FUD IMO. As far as I can see, there are only three criteria that ordinary end users should be considering as a reason for using or not using a codec: - speed (decoding and encoding) - achievable level of quality (this may need to be considered in light of speed differences as well, which currently means ASP codecs have a huge advantage if your requirements call for certain speed ranges) - software support and interoperability
On Sun, Jan 01, 2006 at 11:27:52AM -0500, compn wrote:
bleeding edge? do non-native english people know this word?
yes Diego
participants (3)
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compn -
Diego Biurrun -
Jeff Clagg