Re: [Mjpeg-users] Encoding large DV files to mpeg-1 and mpeg-2

[Steven M. S. <sm...@2B...>]

On Wed, 7 Jan 2004, George Kola wrote:

>        Thanks a lot Steven. Your suggestion is very useful and solved most
> of my problem. I had some problems with my computer setup and took quite

	AH, great - nice when advice works out well.

>        I picked up smilutils-0.1.2 from
> http://users.pandora.be/acp/kino/smilutils.html . I compiled ffmpeg from CVS

	Hmmm, that's quite old.   I know that 0.1.3 was released some time
	ago, not sure where the download link for that is hidden though.

> and used the --with-avcodec-include to point to the include from ffmpeg
> installation. I find that smilutils still looks for libdv. Do you want me to

	Hmmm, that might just be ./configure looking for libdv.  What version
	of libdv are you using?

> try smilutils from cvs ?

	That's what I do ;)

	When you built smilutils with

./configure --with-avcodec --with-avcodec-include=/usr/local/src/ffmpeg/libavcodec

	did you see a line like this in the configure output?

checking libavcodec version (build >4644)... yes
 
	That indicates that the libavcodec includes and library were
	successfully and correctly detected.   If that says "no" then
	look at config.log to find out what went awry.

> 	 More importantly, smil2wav does not support the large DV, I could
> not figure out why. At present, I have an option of generation the mpeg-2

	Hmmm, what is the symptom/error?   I use smil2wav on huge (20GB)
	files without a problem - but then I'm using 'raw DV'.

	What I have seen happen (and it's not consistent from system to system
	which means it could be a threading/race issue) is that sometimes
	using a .avi or .dv file doesn't work but if I create a .smil xml file
	that spans the whole avi/dv then smil2wav will accept that.   Strange.

	I'm wondering if the large files you have are using the ODML format
	or some other (non-standard) method of handling AVI files over 1GB.

> audio stream from mencoder and the video streams using mjpeg-tools and
> mplexing them. Should I be worried about A/V sync problems if I do that ?

	Should work fine - I've done that on occasion.

> > 	  smil2yuv -i 2 redhotridinghood.dv | \
	...
> > 	     y4mscaler -O chromass=420_MPEG2 | \

>          When should I use y4mscalar and when should I not use it. I want

	Always.

	If any scaling or chroma conversion is needed use y4mscaler.

> both mpeg-1 and mpeg-2 and I have lots of CPU (dual xeons 2.8 Ghz with
> hyperthreading). I want vcd mpeg-1 and dvd mpeg-2 and the best quality

	Well, for best performance turn off the hyperthreading - it did 
	nothing but slow things down (I've a dual 2.2 Xeon system from a couple
	years ago).   Some OSs are better at avoiding the slowdown than
	others (the BSD systems treat the pseudo-cpus are full heavyweight
	cpus and that slows things down a lot,  Linux was better but was
	still slower with hyperthreading enabled than if hyperthreading was
	turned off in the BIOS).

	    y4mscaler -S option=cubicCR -O preset=VCD

	or for SVCD/CVD I've had good luck with 

	   y4mscaler -S option=sinc:8 -O preset=CVD

	   (or SVCD - depends how much you want to fit on a CD-R)

	For DVDs there's no scaling involved (unless you want the 1/2 D1
	resolution - in which case the "CVD" preset [352x480] will work fine).
	(hmmm, come to think of it - y4mscaler needs a cropped D1 preset that
	would give 704x480/576 which is also a valid DVD size)

	Try finding smilutils 0.1.3 or the cvs version and see if that
	works better for you.

	Cheers,
	Steven Schultz