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+* ffmpeg can use YUV files as input : 
+
+  ffmpeg /tmp/out.mpg /tmp/test
+
+If will use the files: 
+/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V, 
+/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
+
+The Y files use twice the resolution of the U and V files. They are
+raw files, without header. They can be generated by all decent video
+decoders.
+
+* ffmpeg can use a video4linux compatible video source : 
+
+  ffmpeg /tmp/out.mpg 
+
+  Note that you must activate the right video source and channel
+  before launching ffmpeg. You can use any TV viewer such as xawtv by
+  Gerd Knorr which I find very good.
+
+* There are some importants options to know:
+
+-s size      set frame size                [160x128]
+-f format    set encoding format           [mpeg1]
+-r fps       set frame rate                [25]
+-b bitrate   set the bitrate in kbit/s     [100]
+-t time      set recording time in seconds [10.0]
+
+The frame size can also be: cif, qcif, sqcif and 4cif.
+The encoding format can be mpeg1, h263 or rv10.
+
+Advanced options are:
+
+-d device    set video4linux device name
+-g gop_size  set the group of picture size. 
+             An 'intra' frame is generated every gop_size frames.
+-i           use only intra images (speed up compression, but lower quality).
+-c comment   set the comment string.
+
+Comment strings are only used for Real Video(tm) encoding. Tags are
+used in the comment string. A typical comment string is:
+
+"+title=Test Video +author=FFMpeg +copyright=Free +comment=Generated by FFMpeg 1.0"
+
+The output file can be "-" to output to a pipe. This is only possible
+with mpeg1 and h263 formats. 
+
+* Tips:
+
+- For low bit rate application, use a low frame rate and a small gop
+  size. This is especially true for real video where the Linux player
+  does not seem to be very fast, so it can miss frames. An example is:
+
+  ffmpeg -g 3 -r 3 -t 10 -b 50 -s qcif -f rv10 /tmp/b.rm
+
+- The parameter 'q' which is displayed while encoding is the current
+  quantizer. The value of 1 indicates that a very good quality could
+  be achieved. The value of 31 indicates the worst quality. If q=31
+  too often, it means that the encoder cannot compress enough to meet
+  your bit rate. You must either increase the bit rate, decrease the
+  frame rate or decrease the frame size.
+