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https://github.com/mpv-player/mpv
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Nits and corrections suggested by The Wanderer
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@15468 b3059339-0415-0410-9bf9-f77b7e298cf2
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@ -531,8 +531,8 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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determining what type of content you are dealing with.
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If your source material comes from DVD or broadcast/cable/satellite
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TV, it will be stored in one of two formats: NTSC for North
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America and Japan, and PAL for Europe, etc.
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But it is important to realize that this is just the formatting for
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America and Japan, PAL for Europe, etc.
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It is important to realize, however, that this is just the formatting for
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presentation on a television, and often does
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<emphasis role="bold">not</emphasis> correspond to the
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original format of the movie.
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@ -558,7 +558,7 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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<listitem><para>
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<emphasis role="bold">PAL video</emphasis>: Recorded with a PAL
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video camera at 50 fields per second.
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A field consists of just the even or odd numbered lines of a
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A field consists of just the odd- or even-numbered lines of a
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frame.
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Television was designed to refresh these in alternation as a
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cheap form of analog compression.
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@ -577,12 +577,13 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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</para></listitem>
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<listitem><para>
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<emphasis role="bold">Animation</emphasis>: Usually drawn at
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24fps, but animation also comes in mixed-framerate varieties.
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24fps, but also comes in mixed-framerate varieties.
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</para></listitem>
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<listitem><para>
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<emphasis role="bold">Computer Graphics (CG)</emphasis>: Can be
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any framerate, but 24 and 30 fps are the most frequently
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encountered in NTSC regions, and 25 fps in PAL regions.
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any framerate, but some are more common than others; 23 and
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30 frames per second are typical for NTSC, and 25fps is typical
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for PAL.
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</para></listitem>
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<listitem><para>
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<emphasis role="bold">Old Film</emphasis>: Various lower
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@ -596,7 +597,7 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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<para>
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Movies consisting of frames are referred to as progressive,
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while those consisting of independent fields are called
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interlaced, or sometimes video, although this latter term is
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either interlaced or video - though this latter term is
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ambiguous.
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</para>
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<para>
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@ -623,14 +624,14 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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<listitem><para>
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<emphasis role="bold">PAL 2:2 pulldown</emphasis>: The nicest of
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them all.
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Each frame is shown for two fields duration, by extracting the
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Each frame is shown for the duration of two fields, by extracting the
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even and odd lines and showing them in alternation.
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If the original material is 24fps, this process speeds up the
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movie by 4%.
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</para></listitem>
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<listitem><para>
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<emphasis role="bold">PAL 2:2:2:2:2:2:2:2:2:2:2:3 pulldown</emphasis>:
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Every 12th frame is shown for three fields duration, instead of
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Every 12th frame is shown for the duration of three fields, instead of
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just two.
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This avoids the 4% speedup issue, but makes the process much
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more difficult to reverse.
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@ -639,8 +640,8 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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</para></listitem>
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<listitem><para>
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<emphasis role="bold">NTSC 3:2 telecine</emphasis>: Frames are
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shown alternatively for 3 fields or 2 fields duration.
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This gives a fieldrate 5/2 times the original framerate.
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shown alternately for the duration of 3 fields or 2 fields.
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This gives a fieldrate 2.5 times the original framerate.
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The result is also slowed down very slightly from 60 fields per
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second to 59.94 fields per second to maintain NTSC fieldrate.
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</para></listitem>
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@ -652,30 +653,31 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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</itemizedlist>
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<para>
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There are also methods for converting between NTSC and PAL video.
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Such topics are beyond the scope of this guide.
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There are also methods for converting between NTSC and PAL video,
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but such topics are beyond the scope of this guide.
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If you encounter such a movie and want to encode it, your best
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bet is to find a copy in the original format.
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NTSC/PAL conversion is highly destructive and cannot be reversed
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cleanly, so your encode will greatly suffer if it is made from a
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converted source.
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Conversion between these two formats is highly destructive and
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cannot be reversed cleanly, so your encode will greatly suffer
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if it is made from a converted source.
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</para>
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<para>
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When video is stored on DVD, consecutive pairs of fields are
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grouped as a frame, even though they are not intended to be shown
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at the same moment in time.
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The MPEG-2 standard used on DVD and digital TV provides a way to
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encode the original progressive frames, and store the number of
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fields for which each should be shown in the frame headers.
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If this method has been used, the term "soft telecine" will often
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be used to describe the movie, since the process only directs the
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The MPEG-2 standard used on DVD and digital TV provides both a
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way to encode the original progressive frames, and to store in
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the header of each frame the number of fields for which it should
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be shown.
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If this method has been used, the movie will often be described
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as "soft-telecined", since the process only directs the
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DVD player to apply pulldown to the movie rather than altering
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the movie itself.
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This case is highly preferable since it can easily be reversed
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(actually ignored) by the encoder, and since it preserves maximal
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quality.
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However, many DVD and broadcast production studios do not use
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proper encoding techniques, and instead produce movies with
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proper encoding techniques but instead produce movies with
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"hard telecine", where fields are actually duplicated in the
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encoded MPEG-2.
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</para>
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@ -706,14 +708,13 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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</para></listitem>
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<listitem><para>
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If <application>MPlayer</application> never shows the framerate
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change, and every single frame with motion appears combed, your
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changing, and every single frame with motion appears combed, your
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movie is NTSC video at 59.94 fields per second.
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</para></listitem>
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<listitem><para>
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If <application>MPlayer</application> never shows the framerate
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change, and two frames out of every five appear combed, your
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movie is "hard telecined"
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24fps content.
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movie is "hard telecined" 24fps content.
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</para></listitem>
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</itemizedlist>
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@ -744,22 +745,34 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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</sect2>
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<sect2 id="menc-feat-dvd-mpeg4-2pass">
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<title>Constant Quantizer vs. two pass</title>
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<title>Constant quantizer vs. multi-pass</title>
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<para>
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It is possible to encode your movie at a wide range of qualities.
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With modern video encoders and a bit of pre-codec compression
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(downscaling and denoising), it is possible to achieve very good
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quality at 700 MB, for a 90-110 minute widescreen movie.
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And all but the longest movies can be encoded with near-perfect
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Furthermore, all but the longest movies can be encoded with near-perfect
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quality at 1400 MB.
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</para>
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<para>
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There are three approaches to encoding the video: constant bitrate
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(CBR), constant quantizer, and two pass (ABR, or average bitrate).
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(CBR), constant quantizer, and multi-pass (ABR, or average bitrate).
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</para>
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<note><title>Note:</title>
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<para>
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Most codecs which support ABR encode only support two pass encode
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while some others such as <systemitem class="library">x264</systemitem>
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and <systemitem class="library">libavcodec</systemitem> support
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multi-pass, which slightly improves quality at each pass,
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yet this improvement is no longer noticeable after the 6th or so pass.
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Therefore, in this section, two pass and multi-pass will be used
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interchangeably.
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</para>
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</note>
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<para>
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In each of these modes, <systemitem class="library">libavcodec</systemitem>
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breaks the video frame into 16x16 pixel macroblocks and then applies a
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@ -1596,8 +1609,8 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
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deinterlace or not.
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While deinterlacing will make your movie usable on progressive
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scan displays such a computer monitors and projectors, it comes
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at a cost: The field rate of 50 or 59.94 fields per second
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is halved to 25 or 29.97 frames per second, and roughly half
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at a cost: The fieldrate of 50 or 59.94 fields per second
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is halved to 25 or 29.97 frames per second, and roughly half of
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the information in your movie will be lost during scenes with
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significant motion.
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</para>
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