mirror of https://github.com/mpv-player/mpv
New section: choosing the video codec for your encode: what to consider before picking it.
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@17250 b3059339-0415-0410-9bf9-f77b7e298cf2
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@ -1350,6 +1350,111 @@ Do not do this! Always use a file or CD/DVD/etc device as input.
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</para>
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</sect2>
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<sect2 id="menc-feat-dvd-mpeg4-codec">
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<title>Choosing the video codec</title>
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<para>
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Choosing the video codec to use depends on several factors, some of
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which widely depend on personal taste and technical constraints.
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</para>
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<itemizedlist>
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<listitem><para>
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<emphasis role="bold">Compression efficiency</emphasis>:
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It's quite easy to understand that newer-generation codecs are made
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to yield better picture quality than previous generations.
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Therefore, you cannot be wrong
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<footnote id='fn-menc-feat-dvd-mpeg4-codec-cpu'>
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<para>Be careful, however: decoding DVD-resolution MPEG-4 AVC videos
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requires a fast machine (i.e. a Pentium 4 over 1.5Ghz or a Pentium M
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over 1Ghz).
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</para></footnote>
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by choosing MPEG-4 AVC codecs like
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<systemitem class="library">x264</systemitem> instead of MPEG-4 ASP codecs
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such as <systemitem class="library">libavcodec</systemitem> MPEG-4 or
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<systemitem class="library">XviD</systemitem>.
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(To get a better grasp of what the fundamental differences between
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MPEG-4 ASP and MPEG-4 AVC are, you would be well advised to read the entry
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"<ulink url="http://guru.multimedia.cx/?p=10">15 reasons why MPEG4 sucks</ulink>"
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from Michael Niedermayer's blog.)
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Likewise, you should get better quality using MPEG-4 ASP instead
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of MPEG-2 codecs.
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</para>
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<para>
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However, newer codecs which are in heavy development can suffer from
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bugs which have not yet been noticed and which can ruin an encode.
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This is simply the tradeoff for using bleeding-edge technology.
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</para>
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<para>
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What's more, beginning to use a new codec requires that you spend some
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time becoming familiar with its available options, so that you know what
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to adjust to achieve a desired picture quality.
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</para></listitem>
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<listitem><para>
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<emphasis role="bold">Hardware compatibility</emphasis>:
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It usually takes a long time for standalone video players to begin to
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include support for the latest video codecs.
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As a result, most only support MPEG-2 and MPEG-4 ASP
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(beware: usually, not all MPEG-4 ASP features are supported).
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Please refer to the technical specs of your player (if they are available),
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or Google around for more information.
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</para></listitem>
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<listitem><para>
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<emphasis role="bold">Best quality per encoding time</emphasis>:
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Codecs that have been around for some time (such as
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<systemitem class="library">libavcodec</systemitem> MPEG-4 and
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<systemitem class="library">XviD</systemitem>) are usually heavily
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optimized with all kinds of smart algorithms and SIMD assembly code.
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That's why they tend to yield the best quality per fps.
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However, they may have some very advanced options that, if enabled,
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will make the encode really slow for marginal gains.
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</para>
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<para>
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If you are after blazing speed you should stick around the default
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settings of the video codec (which doesn't mean you should not experiment
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with some of the options which are mentioned in other sections
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of this guide).
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</para>
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<para>
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You may also consider choosing a codec which can do multi-threaded
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processing.
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<systemitem class="library">libavcodec</systemitem> MPEG-4 does
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allow that, resulting in small speed gains at the price of lower
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picture quality.
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<systemitem class="library">XviD</systemitem> has some experimental
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patches available to boost encoding speed, by about 40-60% in typical
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cases, with low picture degradation.
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<systemitem class="library">x264</systemitem> also allows multi-threaded
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encoding, which currently speeds-up encoding by 15-30% while lowering
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PSNR by about 0.05dB.
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</para></listitem>
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<listitem><para>
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<emphasis role="bold">Personal taste</emphasis>:
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This is where it gets almost irrational: For the same reason that some
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hung on to DivX 3 for years when newer codecs were already doing wonders,
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some folks will prefer <systemitem class="library">XviD</systemitem>
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or <systemitem class="library">libavcodec</systemitem> MPEG-4 over
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<systemitem class="library">x264</systemitem>.
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</para>
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<para>
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Make your own judgment, and don't always listen to what some people will
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tell you to do or think: The best codec is the one you master the best,
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and the one that looks best to your eyes on your display
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<footnote id='fn-menc-feat-dvd-mpeg4-codec-playback'>
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<para>The same encode may not look the same on someone else's monitor or
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when played back by a different decoder, so future-proof your encodes by
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playing them back on different setups.</para></footnote>!
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</para></listitem>
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</itemizedlist>
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<para>
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Please refer to the section
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<link linkend="menc-feat-selecting-codec">selecting codecs and container formats</link>
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to get a list of supported codecs.
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</para>
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</sect2>
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<sect2 id="menc-feat-dvd-mpeg4-audio">
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<title>Audio</title>
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