feat: Update slideshow error guidance and standard resolution recommendations for better user clarity

app.py

@@ -152,9 +152,14 @@ Please analyze the error and generate a corrected command that addresses the spe
 
 COMMON SLIDESHOW ERROR FIXES:
 - If you see "do not match the corresponding output link" → Images have different dimensions, use scale+pad approach
-- If you see "Padded dimensions cannot be smaller than input dimensions" → Fix pad calculation or use 1920x1080 standard
+- If you see "Padded dimensions cannot be smaller than input dimensions" → Fix pad calculation or use standard resolution (1920x1080 or 1080x1920)
 - If you see "Failed to configure input pad" → Check scale and pad syntax, ensure proper filter chain
-- If you see "Invalid argument" in filters → Simplify filter_complex syntax and check parentheses"""
+- If you see "Invalid argument" in filters → Simplify filter_complex syntax and check parentheses
+
+FORMAT DETECTION KEYWORDS:
+- "vertical", "portrait", "9:16", "TikTok", "Instagram Stories", "phone" → Use 1080x1920
+- "horizontal", "landscape", "16:9", "YouTube", "TV" → Use 1920x1080 (default)
+- "square", "1:1", "Instagram post" → Use 1080x1080"""
 
     user_content += "\n\nYOUR RESPONSE:"
 
@@ -186,17 +191,17 @@ Key requirements:
 CRITICAL SLIDESHOW GUIDANCE:
 When creating slideshows from multiple images with different dimensions, ALWAYS follow this proven pattern:
 
-1. CHOOSE A STANDARD RESOLUTION: Pick 1920x1080 (1080p) as the target resolution for all slideshows
-2. USE SIMPLE SCALE+PAD APPROACH: For each image, scale to fit within 1920x1080 maintaining aspect ratio, then pad with black bars
+1. CHOOSE A STANDARD RESOLUTION: Pick 1920x1080 (1080p) as the default target resolution for slideshows, UNLESS the user explicitly requests a different format (e.g., "vertical video", "9:16 ratio", "portrait mode", "TikTok format" → use 1080x1920)
+2. USE SIMPLE SCALE+PAD APPROACH: For each image, scale to fit within the chosen resolution maintaining aspect ratio, then pad with black bars
 3. PROVEN SLIDESHOW PATTERN:
    ```
    ffmpeg -loop 1 -t 3 -i image1.jpg -loop 1 -t 3 -i image2.jpg -filter_complex "[0]scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v0];[1]scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v1];[v0][v1]concat=n=2:v=1:a=0" -c:v libx264 -pix_fmt yuv420p -movflags +faststart output.mp4
    ```
 
 4. SLIDESHOW RULES:
-   - Always use 1920x1080 as target resolution for consistency
-   - Always use scale=1920:1080:force_original_aspect_ratio=decrease
-   - Always use pad=1920:1080:(ow-iw)/2:(oh-ih)/2 for centering
+   - Use 1920x1080 as target resolution by default, adjust if user specifies format
+   - For horizontal: scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2
+   - For vertical: scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2
    - Always add setsar=1 after padding to fix aspect ratio issues
    - Use 3-second duration per image by default (-t 3)
    - For 3+ images, extend the pattern: [v0][v1][v2]concat=n=3:v=1:a=0