Add support for insta360 single-file format (#1024)

* Add support for insta360 single-file format

* Improve some variable names

* Add documentation for crop_percentage parameter

Co-authored-by: Matthew Tancik <tancik@berkeley.edu>

nerfstudio/process_data/insta360_utils.py

@@ -48,11 +48,6 @@ def get_insta360_filenames(data: Path) -> Tuple[Path, Path]:
     filename_back = data.parent / stem_back
     filename_front = data.parent / stem_front
 
-    if not filename_back.exists():
-        raise FileNotFoundError(f"Could not find {filename_back}")
-    if not filename_front.exists():
-        raise FileNotFoundError(f"Could not find {filename_front}")
-
     return filename_back, filename_front
 
 
@@ -71,6 +66,8 @@ def convert_insta360_to_images(
         video_back: Path to the back video.
         output_dir: Path to the output directory.
         num_frames_target: Number of frames to extract.
+        crop_percentage: Percentage used to calculate the cropped dimentions of extracted frames. Currently used to crop
+         out the curved portions of the fish-eye lens.
         verbose: If True, logs the output of the command.
     Returns:
         A tuple containing summary of the conversion and the number of extracted frames.
@@ -123,3 +120,71 @@ def convert_insta360_to_images(
     CONSOLE.log("[bold green]:tada: Done converting insta360 to images.")
 
     return summary_log, num_final_frames
+
+
+def convert_insta360_single_file_to_images(
+    video: Path,
+    image_dir: Path,
+    num_frames_target: int,
+    crop_percentage: float = 0.7,
+    verbose: bool = False,
+) -> Tuple[List[str], int]:
+    """Converts a video into a sequence of images.
+
+    Args:
+        video: Path to the video.
+        output_dir: Path to the output directory.
+        num_frames_target: Number of frames to extract.
+        crop_percentage: Percentage used to calculate the cropped dimentions of extracted frames. Currently used to crop
+         out the curved portions of the fish-eye lens.
+        verbose: If True, logs the output of the command.
+    Returns:
+        A tuple containing summary of the conversion and the number of extracted frames.
+    """
+
+    with status(msg="Converting video to images...", spinner="bouncingBall", verbose=verbose):
+        # delete existing images in folder
+        for img in image_dir.glob("*.png"):
+            if verbose:
+                CONSOLE.log(f"Deleting {img}")
+            img.unlink()
+
+        num_frames = get_num_frames_in_video(video)
+        if num_frames == 0:
+            CONSOLE.print(f"[bold red]Error: Video has no frames: {video}")
+            sys.exit(1)
+
+        spacing = num_frames // (num_frames_target // 2)
+        vf_cmds = []
+        if spacing > 1:
+            vf_cmds = [f"thumbnail={spacing}", "setpts=N/TB"]
+        else:
+            CONSOLE.print("[bold red]Can't satify requested number of frames. Extracting all frames.")
+
+        vf_cmds_back = vf_cmds.copy()
+        vf_cmds_front = vf_cmds.copy()
+
+        vf_cmds_back.append(
+            f"crop=ih*{crop_percentage}:ih*{crop_percentage}:ih*({crop_percentage}/4):ih*({crop_percentage}/4)"
+        )
+        vf_cmds_front.append(
+            f"crop=ih*{crop_percentage}:ih*{crop_percentage}:iw/2+ih*{crop_percentage/4}:ih*{crop_percentage/4}"
+        )
+
+        front_ffmpeg_cmd = f"ffmpeg -i {video} -vf {','.join(vf_cmds_front)} -r 1 {image_dir / 'frame_%05d.png'}"
+        back_ffmpeg_cmd = f"ffmpeg -i {video} -vf {','.join(vf_cmds_back)} -r 1 {image_dir / 'back_frame_%05d.png'}"
+
+        run_command(back_ffmpeg_cmd, verbose=verbose)
+        run_command(front_ffmpeg_cmd, verbose=verbose)
+
+        num_extracted_frames = len(list(image_dir.glob("frame*.png")))
+        for i, img in enumerate(image_dir.glob("back_frame_*.png")):
+            img.rename(image_dir / f"frame_{i+1+num_extracted_frames:05d}.png")
+
+    num_final_frames = len(list(image_dir.glob("*.png")))
+    summary_log = []
+    summary_log.append(f"Starting with {num_frames} video frames")
+    summary_log.append(f"We extracted {num_final_frames} images")
+    CONSOLE.log("[bold green]:tada: Done converting insta360 to images.")
+
+    return summary_log, num_final_frames