| 
      | Digital Video (DV)
	  ---> MPEG-4 | 
      | Here is a 3 step guide to convert a DV tape to a compressed AVI
	  MPEG-4 movie clip under linux using transcode. For a
	   selection of a video codec implementation supported by
	   transcode consult the  modules info-page. 
	     You need Arne Schirmacher's nice tool dvgrab
		to transfer the DV tape to disk. Make sure, you use
		the "--format dv2" option and maybe "--autosplit" to split
		the tape into small pieces. Use AVI files, since
		libdv sound seems to be broken. Optionally, use 
 tcprobe -i  file.avi
 
 to find out important parameters: For example:
 
[tcprobe] RIFF data, AVI video
[avilib] V: 25.000 fps, codec=dvsd, frames=633, width=720, height=576 [avilib] A: 48000 Hz, format=0x01, bits=16, channels=2, bitrate=1536
		 kbps,
 [avilib]    633 chunks, 4861528 bytes
 [tcprobe] summary for test-2002.10.04_14-47-25.avi, (*) = not default, 0 = not detected
 import frame size: -g 720x576 [720x576]
 frame rate: -f 25.000 [25.000] frc=3
 audio track: -a 0 [0] -e 48000,16,2 [48000,16,2] -n 0x1 [0x2000] (*)
                   bitrate=1536 kbps
 length: 633 frames, frame_time=40 msec
 
 
		 Fortunately, the auto-probing feature
		of transcode takes care of these details.
		 
 
  To encode the clips, we have a number of options:
		 
		    writing a shell script, that feeds transcode with each
		   file,
		    using avimerge to create a single
		       input file,
		    using the directory mode with option "-i". This
		       works only in connection with the import module import_dv.so.
		  AVI-fileHere,
		 we use a single AVI-file file.avi with "dvsd" codec
		 as an example:
		  
		   
		     | transcode | -i file.avi -x dv,avi |  |  | -I 1 -C 1 -z -k |   | -o file-divxmp3.avi -y divx4 |  We use import_avi.so to extract the audio,
	   which works flawless. Note that the audio is found in two
	   places in the AVI-file. Firstly, interleaved in the DV video
	   frame and secondly, the PCM audio track itself.
	   This makes it possible to use the import module "dv" for audio
	   extraction as long libdv is broken.
 Note: some non-dvgrab produced AVI-files may have the audio
	   ripped from the DV frames. In this case, you must use "-x
	   dv,avi" or "-x dv,X", were X is one of (raw,mp3,ac3).
 You can also reduce
	   the picture to a quarter size "-r 2" to get rid of
	   the interlace artifacts and don't need the de-interlace
	   option "-I 1". This option is the fastes de-interlacing
	   available, but is a simple interpolation.
	   You might also want to try
	   out the anti-aliasing feature with "-C 1" to process the
	   whole frame but this is slow.
	   The option "-z -k" flips the frame and make the
	   necessary color space changes for the encoder.
 DV streamPut all AVI-files or raw DV stream into a subdirectory,
	   e.g., named "tape/".
	    
	     
	       | transcode | -i tape/ |  |  | -I 3 -C 2 -z -k |   | -o tape-divxmp3.avi -y divx4 |  The necessary import module is autodetected. tccat extracts
     the video stream of all AVI-files and concatenates them together to
     make the clips appear as a single DV stream for transcode.
     Here, the de-interlace option "-I 3",
     which drops one half-frame and interpolates by zooming to full
     frame size and, in principle, removes the interlace artifacts. We also try
	   the anti-aliasing feature with "-C 2" to process the
	   full frame afterwards, but this is slow.
 
  Well, that's it. Use avimerge to glue the
     matching clips together and burn the resulting file
     to CD.
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