Exposed number of actual frames to extract with ffmpeg for more transparency (#1683)

* Exposed number of actual frames to extract for more transparency

* Fixed off-by-one error in calculation of frames to extract.

* Added math import

* Switched print statements to CONSOLE.print

---------

Co-authored-by: jackson-waschura <jwaschur@calpoly.edu>

nerfstudio/process_data/process_data_utils.py

@@ -14,6 +14,7 @@
 
 """Helper utils for processing data into the nerfstudio format."""
 
+import math
 import os
 import shutil
 import sys
@@ -141,7 +142,7 @@ def convert_video_to_images(
         if num_frames == 0:
             CONSOLE.print(f"[bold red]Error: Video has no frames: {video_path}")
             sys.exit(1)
-        print("Number of frames in video:", num_frames)
+        CONSOLE.print("Number of frames in video:", num_frames)
 
         out_filename = image_dir / "frame_%05d.png"
         ffmpeg_cmd = f'ffmpeg -i "{video_path}"'
@@ -157,6 +158,7 @@ def convert_video_to_images(
         spacing = num_frames // num_frames_target
         if spacing > 1:
             ffmpeg_cmd += f" -vf thumbnail={spacing},setpts=N/TB{crop_cmd} -r 1"
+            CONSOLE.print("Number of frames to extract:", math.ceil(num_frames / spacing))
         else:
             CONSOLE.print("[bold red]Can't satisfy requested number of frames. Extracting all frames.")
             ffmpeg_cmd += " -pix_fmt bgr8"