[MPlayer-dev-eng] usingmencoder to make movie =?iso-8859-1?q?ofgraphics visualization?= frames.

[lists at pedro.larroy.com]

Hi

I'm also using mplayer/mencoder for scientific projects and I do fine
with -vo png:z=0, that way the pngs are not compressed at all.

Regards.


On Tue, Aug 16, 2005 at 03:08:30AM +0200, Ivo wrote:
> Hi,
> 
> On Tuesday 16 August 2005 02:28, don fisher wrote:
> > I attempted using the conversion to png. For some reason, my 64bit
> > Opteron version of mencoder
> > (mplayer-1.0-0.15.pre6a.1.fc3.rf.x86-64.rpm)
> > segfaults with png. I was able to do the decoding on my 32 bit laptop
> > without problems. In this damn litigious society it is always hard to
> > find the rpm's with all of the codecs in them.
> 
> Always use the latest version of MPlayer, preferably CVS, when reporting 
> bugs. This could be a bug in MPlayer, but might as well be a bug in libpng.
> Also, bugreports should go to the mplayer-users mailinglist.
> 
> > I would prefer to use a raw rather that compressed format if possible.
> > It takes about 4 times as long to convert from tiff to png than it
> > does to make the movie using "high quality", non real time parameters.
> > As you know, any of these lossless entropy based encoders are slow,
> > especially if they are adaptive.
> >
> > My data files are 1024x1024 pixels, and the tiff tiles are 3148650
> > bytes long. 3148650 - 3*1024*1024 = 2922 bytes for Tiff color maps
> > etc. So I am assuming the data is in raw format plus the header. I
> > inquired about the SGI format since it is also basically raw, but big
> > endian. I thought TGA could represent data in raw format, but no
> > conversion was mentioned. (My disk space is cheap!).
> >
> > Under section 3.1, Selecting codecs & format, it includes raw as one
> > of the options. Is there an example of how this would be implemented?
> >   I assume the image parameters would be included under type, but
> > inclusion of the color maps is not obvious.
> >
> > The more I look into Tiff, the worse it gets. It can be simple, but
> > the general case can really get ugly:-)
> 
> At first, keep it simple. I'm no TIFF expert, but IIRC you can put almost 
> anything in TIFF, including LZW or JPEG compressed images. If you implement 
> a TIFF decoder for MPlayer, just support raw 24-bit TIFF only. If somebody 
> needs <your-favorite-compression-scheme>-TIFF support, he or she can add 
> that later.
> 
> For an example implementation of reading a tiff file, you could read the 
> source of tifftopnm, though they read a lot more varients of TIFF (but by 
> no means every flavour; see man tifftopnm), or google around a bit.
> 
> Conversion to TGA can be done similar to conversion to PNG:
> 
> convert foo.tiff bar.tga			or
> tifftopnm foo.tiff | ppmtotga -rgb > bar.tga
> 
> BTW the 2922 bytes you mention is probably just an overly bloated TIFF 
> header. I don't see how a true color 24-bit image can have a color map 
> (except when it maps to a much larger colorspace, but I think that's 
> unlikely and 2922 bytes won't be enought space then).
> 
> BTW2 please don't top post!
> 
> --Ivo
> 
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-- 
Pedro Larroy Tovar, pedro at larroy dot com 
Make debian mirrors with debian-multimirror: http://pedro.larroy.com/deb_mm/
   * Las patentes de programación son nocivas para la innovación * 
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