Adding logos to mp4 with Avisynth

[Bencuri]

I would like to know if this one is still the recommended script for adding logos to videos?

a1=avisource("movie.avi")
a2=ImageReader("logo1.png")
a3=ImageReader("logo1.png",pixel_type="RGB32").ShowAlpha(pixel_type="RGB32")
Overlay(a1,a2,mask=a3)

I am not sure though if this will work because my color codes are these:

LWLibavVideoSource("video.mpg") 
ColorMatrix(mode="rec.601->rec.709")

I am converting to mp4. I want to know as well how to merge this adding logo command with my conversion code? This a1 a2... method is quite new to me.

This is my full code so far, the logo procedure should be added to this:

LWLibavVideoSource("video.mpg") 
ColorMatrix(mode="rec.601->rec.709")
Crop(0,8,-0,-0)
QTGMC()
SMDegrain(thsad=1000, tr=3, prefilter=4)
nnedi3_rpow2(2, cshift="Spline36Resize", fwidth=960, fheight=720)
aWarpSharp2(depth=5)
CAS(0.5)
nnedi3_rpow2(2, cshift="Spline36Resize")
CropResize(1920,1080,  CropDAR=4.0/3.0, Resizer="Resize8", Borders=true)
aWarpSharp2(depth=5)
CAS(0.5)
Prefetch(4)

I would like to add the logo to the top right corner in the black area of the letterbox.

[jagabo]

Something like:

LWLibavVideoSource("video.mpg") 
ColorMatrix(mode="rec.601->rec.709")
Crop(0,8,-0,-0)
QTGMC()
SMDegrain(thsad=1000, tr=3, prefilter=4)
nnedi3_rpow2(2, cshift="Spline36Resize", fwidth=960, fheight=720)
aWarpSharp2(depth=5)
CAS(0.5)
nnedi3_rpow2(2, cshift="Spline36Resize")
CropResize(1920,1080,  CropDAR=4.0/3.0, Resizer="Resize8", Borders=true)
aWarpSharp2(depth=5)
CAS(0.5)
a2=ImageReader("logo1.png")
a3=ImageReader("logo1.png",pixel_type="RGB32").ShowAlpha(pixel_type="RGB32")
Overlay(last,a2,mask=a3)

Prefetch(4)

[Bencuri]

I see, thanks. I thought you need to wrap the whole thing into that a1 a2 stuff right in the beginning, it is much more simple than that.

[jagabo]

I guessed you were adding borders with CropResize() after upscaling and wanted a small logo at the top left. If your source had black borders and you wanted a bigger logo (relative to the frame size) you could Overlay before upscaling.