Use arg list, rename timestamp variables

Author: Daniel Flores

test/generate_reference_resources.py

@@ -32,15 +32,39 @@ def main():
             # so that the name of reference frames matches the index when accessing that
             # frame in the Python decoder.
             frame_name = f"{frame:06d}"
-            cmd = f"""ffmpeg -y -i {VIDEO_PATH} -map 0:{stream} -vf select=eq(n\\,{frame}) -vsync vfr -q:v 2 {VIDEO_PATH}.stream{stream}.frame{frame_name}.bmp"""
-            subprocess.run(cmd.split(), check=True)
+            cmd = [
+                "ffmpeg",
+                "-y",
+                "-i",
+                VIDEO_PATH,
+                "-map",
+                f"0:{stream}",
+                "-vf",
+                f"select=eq(n\\,{frame})",
+                "-vsync",
+                "vfr",
+                "-q:v",
+                "2",
+                f"{VIDEO_PATH}.stream{stream}.frame{frame_name}.bmp",
+            ]
+            subprocess.run(cmd, check=True)
 
     # Extract individual frames at specific timestamps, including the last frame of the video.
-    seek_ts = [6.0, 6.1, 10.0, 12.979633]
-    ts_name = [f"{seek_ts:06f}" for seek_ts in seek_ts]
-    for ts, name in zip(seek_ts, ts_name):
-        cmd = f"ffmpeg -y -ss {ts} -i {VIDEO_PATH} -frames:v 1 {VIDEO_PATH}.time{name}.bmp"
-        subprocess.run(cmd.split(), check=True)
+    seek_timestamp = [6.0, 6.1, 10.0, 12.979633]
+    timestamp_name = [f"{seek_timestamp:06f}" for seek_timestamp in seek_timestamp]
+    for timestamp, name in zip(seek_timestamp, timestamp_name):
+        cmd = [
+            "ffmpeg",
+            "-y",
+            "-ss",
+            str(timestamp),
+            "-i",
+            VIDEO_PATH,
+            "-frames:v",
+            "1",
+            f"{VIDEO_PATH}.time{name}.bmp",
+        ]
+        subprocess.run(cmd, check=True)
 
     # This video was generated by running the following:
     # conda install -c conda-forge x265
@@ -51,8 +75,20 @@ def main():
     FRAMES = [5]
     for frame in FRAMES:
         frame_name = f"{frame:06d}"
-        cmd = f"""ffmpeg -y -i {VIDEO_PATH} -vf select=eq(n\\,{frame}) -vsync vfr -q:v 2 {VIDEO_PATH}.stream0.frame{frame_name}.bmp"""
-        subprocess.run(cmd.split(), check=True)
+        cmd = [
+            "ffmpeg",
+            "-y",
+            "-i",
+            VIDEO_PATH,
+            "-vf",
+            f"select=eq(n\\,{frame})",
+            "-vsync",
+            "vfr",
+            "-q:v",
+            "2",
+            f"{VIDEO_PATH}.stream0.frame{frame_name}.bmp",
+        ]
+        subprocess.run(cmd, check=True)
 
     # This video was generated by running the following:
     # ffmpeg -f lavfi -i testsrc=duration=5:size=640x360:rate=25,format=yuv420p -c:v libaom-av1 -crf 30 -colorspace bt709 -color_primaries bt709 -color_trc bt709 av1_video.mkv
@@ -62,8 +98,20 @@ def main():
 
     for frame in FRAMES:
         frame_name = f"{frame:06d}"
-        cmd = f"""ffmpeg -y -i {VIDEO_PATH} -vf select=eq(n\\,{frame}) -vsync vfr -q:v 2 {VIDEO_PATH}.stream0.frame{frame_name}.bmp"""
-        subprocess.run(cmd.split(), check=True)
+        cmd = [
+            "ffmpeg",
+            "-y",
+            "-i",
+            VIDEO_PATH,
+            "-vf",
+            f"select=eq(n\\,{frame})",
+            "-vsync",
+            "vfr",
+            "-q:v",
+            "2",
+            f"{VIDEO_PATH}.stream0.frame{frame_name}.bmp",
+        ]
+        subprocess.run(cmd, check=True)
 
     for bmp in [f for f in os.listdir(RESOURCES_DIR) if f.endswith(".bmp")]:
         bmp_path = os.path.join(RESOURCES_DIR, bmp)