[LAU] AVSynthesis videos on-line

[Dave Phillips]

Florin Andrei wrote:
> Dave Phillips wrote:
>   
>> Thanks again, Florin. Have you considered writing a HOWTO or a dedicated 
>> Web site for this information ? It's obvious you know it very well, and 
>> it would be great to have a 1-stop web site for it.
>>     
>
> This is standard knowledge in the field of video processing. Anyone who 
> has spent some time with cameras and NLEs and stuff like that will tell 
> you the same things.
>   
I'm learning as I go. I've been following and studying the links you've 
posted, I'm getting a better idea of the work involved and its 
terminology (a non-trivial matter to one without that standard knowledge).

re: Vimeo
>> ... the Vimeo site converts my videos, but I don't know to what format. 
>> Given what you've seen and understand of the site, what would be my 
>> best-choice options for rendering the AVSynthesis images to video ?
>>     
>
> There's no simple answer.
> You have to come up with a procedure to generate the video file that 
> will be uploaded. They have a few recommendations...
>
> http://www.vimeo.com/help/compression
>
> ...which essentially boil down to "H.264 with AAC at 30 or 25 fps", but 
> then turn around and say they convert everything to 24. I guess some 
> experiments are required.
>   
I've been experimenting, but I think I have some other issues to resolve 
first.


> Eugenia Loli-Queru has several HOWTOs regarding the different formats 
> recommended for Vimeo...
>
> http://www.vimeo.com/forums/topic:3671
>
> ...but those are geared towards people using typical NLEs and stuff like 
> that. Even so, it's a bit of a hit-and-miss - her Vegas HOWTO didn't 
> work for me very well with material from an AVCHD camera, it created 
> choppy video. I didn't try yet other methods.
>   
I followed her advice for using mencoder. The results were okay, but I 
noticed that the video pixellated rather obviously during fades, it 
seemed similar to the quantization effect when a low-grade reverb fades out.

> There's a bunch of interconnected decisions that need to be made, going 
> back to the AVS parameters, and that's why I'm saying I'd like to try 
> this software myself before blurting out random advice that may not be 
> so helpful after all.
>   
Understood, though your advice has been and is most welcome here. I'm in 
terra incognita where video is concerned, but suddenly I'm there and I'm 
still getting my bearings.


>   
>> Just to clarify: AVS does no rendering to video at all, it simply 
>> creates the image sequence. I have control over the recorder frame rate 
>> and the image width & height, that's all that's available to me in AVS 
>> itself.
>>     
>
> Yup, that should be enough. The collection of images just needs to be 
> fed into the processing chain, and then all kinds of things can happen: 
> cropping, resizing, interlacing, changing the frame rate, etc. Once 
> you're in the uncompressed domain, almost anything is doable.
>   
I should add that I also have control over the audio sampling rate.

I've configured AVS's output for 25 fps at 640x480, I'll try 720x480 
today. I've looked a bit further into the letterbox problem. The images 
themselves are TARGA-format images that include the black bands. I've 
looked at the code for the image creation but there's no indication that 
the process takes any options to eliminate the letterboxing. I could be 
wrong about that, I'm not a Java programmer. :(  Meanwhile I'll see what 
I can do to crop the TGA images.

I'll report back after more experimentation.

Best,

dp