Re: [Mlt-devel] Debugging MLT Questions

[Jonathan T. <jon...@gm...>]

Awesome!  That will save me some time. =) I just tested the function, and it
works great.
-Jonathan

On Thu, Dec 23, 2010 at 1:03 AM, Dan Dennedy <da...@de...> wrote:

> On Wed, Dec 22, 2010 at 10:22 PM, Dan Dennedy <da...@de...> wrote:
> > On Wed, Dec 22, 2010 at 8:25 PM, Jonathan Thomas
> > <jon...@gm...> wrote:
> >> Dan,
> >> Do you have any code snippets or examples that I can use when debugging
> MLT
> >> to save an image buffer to a file, so I can view what the image looks
> like
> >> at various places inside MLT?  For example, during filter processing
> (i.e.
> >> the affine filter), image buffers are passed around and modified, and
> >> debugging this kind of bug is quite tricky without seeing what is
> happening.
> >
> > Nothing exists now other than the consumers and carefully constructing
> > melt commands. However, ppm is easy to write, and it would be possible
> > to add a mlt_frame function to write a frame's image as ppm. You can
> > see code for reading ppm in src/modules/core/producer_ppm.c.
> >
> void mlt_frame_write_ppm( mlt_frame frame )
> {
>        int width;
>        int height;
>        mlt_image_format format = mlt_image_rgb24;
>        uint8_t *image;
>
>        if ( mlt_frame_get_image( frame, &image, &format, &width, &height, 0
> ) == 0 )
>        {
>                FILE *file;
>                char filename[16];
>
>                sprintf( filename, "frame-%05d.ppm", mlt_frame_get_position(
> frame ) );
>                file = fopen( filename, "wb" );
>                if ( !file )
>                        return;
>                fprintf( file, "P6\n%d %d\n255\n", width, height);
>                fwrite( image, width * height * 3, 1, file );
>                fclose( file );
>        }
> }
>