[MPlayer-dev-eng] using mencoder to make movie of graphics visualization frames.

[don fisher]

Back again;-)

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.

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:-)

Thanks again
don

Hugo González Monteverde wrote:
> Hi Don,
> 
> It may be possible that someone is considering adding other image format 
> support for mplayer. But I guess the best way would be just to convert 
> them to PNG (lossless) so you get your data right. Remember also to 
> scale the video frame (image) to a workable size. It is really pointless 
>   to compose an AVI file made of frames which are 10 megapixels if no 
> monitor would display  it unscaled.
> 
> As for conversion, I would recommend ImageMagick 
> http://www.imagemagick.org/script/index.php It can be batched, as it is 
> command line, and even can be plugged into your program as it exposes an 
> API.
> 
>  From the mencoder man page and altered for png...
> 
> mencoder "mf://*.png" -mf fps=25 -o output.avi -ovc lavc -lavcopts 
> vcodec=mpeg4
> 
> I hope I got what you wanted to do. As for filters, you could scale, but 
> it would be better to scale the image as you convert it.
> 
> Hugo
> 
> 
> don fisher wrote:
> 
>> I am using OpenDX to generate sequences of images showing velocities 
>> etc. from scientific simulation studies. The simulations are lengthy, 
>> so a multiframe file sequence would exceed the allowable file size on 
>> a 32 bit linux system.
>>
>> The package will make an array of single frame tiff files. Mencoder 
>> accepts multiframe sequences of JPEG, PNG, TGA and SGI formats. My 
>> goal is to optimize image quality by presenting uncorrupted data to 
>> the encoder. That eliminates JPEG. Section 7.5 of the MPlayer page 
>> includes the SGI in the title, but is not mentioned anywhere else. I 
>> do not know how to convert from Tiff to PNG or TGA.
>>
>> I know how to write code etc, so suggestions on a filter would be 
>> welcome. Is there any plan (or has someone already done it) to include 
>> Tiff in the list of multiframe readers? I am sure other persons must 
>> have approached this problem before. Any assistance would be appreciated.
>>
>> First posting to this list. I hope it is within scope.
>>
>> don
> 
> 
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> 

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|    Don Fisher				  dfisher at as.arizona.edu  |
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