Upscaling video with different filter on each side

Question

I need scale up video from one DOS game using FFmpeg. But with Nearest-neighbor interpolation on left side and xBR filter on the other one.

Input (320x200)

Output (1280x800)

Here is a command, where's xBR processing whole screen...

ffmpeg
    -i input.avi
    -sws_flags neighbor
    -vcodec libx264 -strict -2
    -preset veryslow -qp 0
    -filter:v "xbr=4"
    output.mp4

Answer 1

Left & right

_{I cropped the image to make the output size smaller just for display purposes.}

This will show the whole video on each side. Left is xbr and right is scale.

Using hstack

ffmpeg -i input.avi -filter_complex \
"[0:v]xbr=4[bg]; \
 [0:v]scale=iw*4:-1:flags=neighbor[fg]; \
 [bg][fg]hstack,format=yuv420p[v]" \
-map "[v]" -map 0:a -movflags +faststart output.mp4

All input streams to hstack must have the same pixel format and same width.

Using pad & overlay

ffmpeg -i input.avi -filter_complex \
"[0:v]xbr=4,pad=iw*2[bg]; \
 [0:v]scale=iw*4:-1:flags=neighbor[fg]; \
 [bg][fg]overlay=w,format=yuv420p[v]" \
-map "[v]" -map 0:a -movflags +faststart output.mp4

This method is slower and more complex than just using hstack.

---

Left & right: With 10 pixel border

ffmpeg -i input.avi -filter_complex \
"[0:v]xbr=4,pad=iw*2+10[bg]; \
 [0:v]scale=iw*4:-1:flags=neighbor[fg]; \
 [bg][fg]overlay=w+10,format=yuv420p[v]" \
-map "[v]" -map 0:a -movflags +faststart output.mp4

---

Split screen: left & right

ffmpeg -i input.avi -filter_complex \
"[0:v]xbr=4[bg]; \
 [0:v]scale=iw*4:-1:flags=neighbor,crop=iw/2:ih:ow:0[fg]; \
 [bg][fg]hstack[v]" \
-map "[v]" -map 0:a -movflags +faststart output.mp4

---

Top & bottom

Using vstack

ffmpeg -i input.avi -filter_complex \
"[0:v]xbr=4[bg]; \
 [0:v]scale=iw*4:-1:flags=neighbor[fg]; \
 [bg][fg]vstack,format=yuv420p[v]" \
-map "[v]" -map 0:a -movflags +faststart output.mp4

All input streams to vstack must have the same pixel format and same width.

Using pad & overlay

ffmpeg -i input.avi -filter_complex \
"[0:v]xbr=4,pad=iw*2[bg]; \
 [0:v]scale=iw*4:-1:flags=neighbor[fg]; \
 [bg][fg]overlay=0:h,format=yuv420p[v]" \
-map "[v]" -map 0:a -movflags +faststart output.mp4

This method is slower and more complex than just using vstack.

---

Split screen: top & bottom

ffmpeg -i input.avi -filter_complex \
"[0:v]xbr=4[bg]; \
 [0:v]scale=iw*4:-1:flags=neighbor,crop=iw:ih/2:0:oh[fg]; \
 [bg][fg]vstack[v]" \
-map "[v]" -map 0:a -movflags +faststart output.mp4