Ken Burns Zoom Refinements (Ping-Pong Loop)

docs/image/convert/image_to_video.md

@@ -25,6 +25,8 @@ The request body must be in JSON format and should include the following paramet
 | `length`    | number | No       | The desired length of the video in seconds (default: 5).    |
 | `frame_rate`| integer| No       | The frame rate of the output video (default: 30).           |
 | `zoom_speed`| number | No       | The speed of the zoom effect (0-100, default: 3).           |
+| `zoom_effect`| string | No       | The type of zoom effect: "linear" (default), "ping-pong".   |
+| `zoom_loop_duration`| number | No | Duration in seconds for a full zoom loop (for ping-pong).   |
 | `webhook_url`| string| No       | The URL to receive a webhook notification upon completion.  |
 | `id`        | string | No       | An optional identifier for the request.                      |
 
@@ -38,6 +40,8 @@ The `validate_payload` decorator in the `routes.v1.image.convert.image_to_video`
         "length": {"type": "number", "minimum": 1, "maximum": 60},
         "frame_rate": {"type": "integer", "minimum": 15, "maximum": 60},
         "zoom_speed": {"type": "number", "minimum": 0, "maximum": 100},
+        "zoom_effect": {"type": "string", "enum": ["linear", "ping-pong", "loop"]},
+        "zoom_loop_duration": {"type": "number", "minimum": 5, "maximum": 400},
         "webhook_url": {"type": "string", "format": "uri"},
         "id": {"type": "string"}
     },
@@ -54,6 +58,8 @@ The `validate_payload` decorator in the `routes.v1.image.convert.image_to_video`
     "length": 10,
     "frame_rate": 24,
     "zoom_speed": 5,
+    "zoom_effect": "ping-pong",
+    "zoom_loop_duration": 5,
     "webhook_url": "https://example.com/webhook",
     "id": "request-123"
 }

routes/v1/image/convert/image_to_video.py

@@ -36,6 +36,8 @@
         "length": {"type": "number", "minimum": 0.1, "maximum": 400},
         "frame_rate": {"type": "integer", "minimum": 15, "maximum": 60},
         "zoom_speed": {"type": "number", "minimum": 0, "maximum": 100},
+        "zoom_effect": {"type": "string", "enum": ["linear", "ping-pong", "loop"]},
+        "zoom_loop_duration": {"type": "number", "minimum": 5, "maximum": 400},
         "webhook_url": {"type": "string", "format": "uri"},
         "id": {"type": "string"}
     },
@@ -48,6 +50,8 @@ def image_to_video(job_id, data):
     length = data.get('length', 5)
     frame_rate = data.get('frame_rate', 30)
     zoom_speed = data.get('zoom_speed', 3) / 100
+    zoom_effect = data.get('zoom_effect', 'linear')
+    zoom_loop_duration = data.get('zoom_loop_duration')
     webhook_url = data.get('webhook_url')
     id = data.get('id')
 
@@ -56,7 +60,7 @@ def image_to_video(job_id, data):
     try:
         # Process image to video conversion
         output_filename = process_image_to_video(
-            image_url, length, frame_rate, zoom_speed, job_id, webhook_url
+            image_url, length, frame_rate, zoom_speed, job_id, webhook_url, zoom_effect, zoom_loop_duration
         )
 
         # Upload the resulting file using the unified upload_file() method

services/v1/image/convert/image_to_video.py

@@ -24,7 +24,7 @@
 from config import LOCAL_STORAGE_PATH
 logger = logging.getLogger(__name__)
 
-def process_image_to_video(image_url, length, frame_rate, zoom_speed, job_id, webhook_url=None):
+def process_image_to_video(image_url, length, frame_rate, zoom_speed, job_id, webhook_url=None, zoom_effect="linear", zoom_loop_duration=None):
     try:
         # Download the image file
         image_path = download_file(image_url, LOCAL_STORAGE_PATH)
@@ -52,12 +52,25 @@ def process_image_to_video(image_url, length, frame_rate, zoom_speed, job_id, we
 
         logger.info(f"Using scale dimensions: {scale_dims}, output dimensions: {output_dims}")
         logger.info(f"Video length: {length}s, Frame rate: {frame_rate}fps, Total frames: {total_frames}")
-        logger.info(f"Zoom speed: {zoom_speed}/s, Final zoom factor: {zoom_factor}")
+        logger.info(f"Zoom speed: {zoom_speed}/s, Final zoom factor: {zoom_factor}, Effect: {zoom_effect}, Loop Duration: {zoom_loop_duration}")
 
         # Prepare FFmpeg command with fps filter to ensure correct frame rate
+        if zoom_effect == "ping-pong":
+            # Using triangle wave for Ping-Pong Zoom (In -> Out) with optional loop frequency
+            loop_period = zoom_loop_duration if zoom_loop_duration else length
+            loop_frames = int(loop_period * frame_rate)
+            if loop_frames < 1: loop_frames = total_frames
+
+            # Formula: 1 + MaxCorrection * (1 - abs(2 * mod(on, loop_frames)/loop_frames - 1))
+            # mod(on, loop_frames) cycles 0 -> loop_frames-1
+            expression = f"1+({zoom_speed}*{length})*(1-abs(2*mod(on,{loop_frames})/{loop_frames}-1))"
+        else: # linear default
+            # Standard linear zoom in
+            expression = f"min(1+({zoom_speed}*{length})*on/{total_frames}, {zoom_factor})"
+
         cmd = [
             'ffmpeg', '-framerate', str(frame_rate), '-loop', '1', '-i', image_path,
-            '-vf', f"scale={scale_dims},zoompan=z='min(1+({zoom_speed}*{length})*on/{total_frames}, {zoom_factor})':d={total_frames}:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':s={output_dims},fps={frame_rate}",
+            '-vf', f"scale={scale_dims},zoompan=z='{expression}':d={total_frames}:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':s={output_dims},fps={frame_rate}",
             '-c:v', 'libx264', '-r', str(frame_rate), '-t', str(length), '-pix_fmt', 'yuv420p', output_path
         ]