Feature Request: Configurable Thumbnail GIF Generation

[akulmehta]

Summary

Make thumbnail GIF generation settings configurable via Django settings, allowing users to customize duration, frame rate, and start position instead of using hardcoded values.

Problem Statement

Currently, thumbnail GIF generation in MediaCMS uses hardcoded values in files/tasks.py (lines ~319-346):

command = [
    settings.FFMPEG_COMMAND,
    "-y",
    "-ss",
    "3",                                          # Hardcoded: start at 3 seconds
    "-i",
    media.media_file.path,
    "-hide_banner",
    "-vf",
    "scale=344:-1:flags=lanczos,fps=1",          # Hardcoded: 1 fps
    "-t",
    "25",                                         # Hardcoded: 25 seconds duration
    "-f",
    "gif",
    tf,
]

Limitations:

1. Fixed duration: Always captures 25 seconds, regardless of video length
2. Cannot sample entire video: For long videos (30+ minutes), the GIF only shows content from the first 28 seconds (3s start + 25s duration)
3. High frame rate: 1 fps generates 25 frames, creating large GIF files
4. Not user-configurable: Requires code modification to change behavior

This contrasts with sprite generation, which already uses configurable SPRITE_NUM_SECS to sample frames across the entire video duration.

Proposed Solution

Add three new Django settings to control GIF generation:

New Settings

# cms/settings.py

# Thumbnail GIF generation settings
THUMBNAIL_GIF_START = 3          # Start position in seconds
THUMBNAIL_GIF_DURATION = 25      # Duration to capture in seconds  
THUMBNAIL_GIF_FPS = 1            # Frames per second

Code Changes

File: files/tasks.py (around line 319)

# Before (hardcoded):
if profile.extension == "gif":
    tf = create_temp_file(suffix=".gif")
    command = [
        settings.FFMPEG_COMMAND,
        "-y",
        "-ss",
        "3",
        "-i",
        media.media_file.path,
        "-hide_banner",
        "-vf",
        "scale=344:-1:flags=lanczos,fps=1",
        "-t",
        "25",
        "-f",
        "gif",
        tf,
    ]

# After (configurable):
if profile.extension == "gif":
    tf = create_temp_file(suffix=".gif")
    gif_start = getattr(settings, 'THUMBNAIL_GIF_START', 3)
    gif_duration = getattr(settings, 'THUMBNAIL_GIF_DURATION', 25)
    gif_fps = getattr(settings, 'THUMBNAIL_GIF_FPS', 1)
    
    command = [
        settings.FFMPEG_COMMAND,
        "-y",
        "-ss",
        str(gif_start),
        "-i",
        media.media_file.path,
        "-hide_banner",
        "-vf",
        f"scale=344:-1:flags=lanczos,fps={gif_fps}",
        "-t",
        str(gif_duration),
        "-f",
        "gif",
        tf,
    ]

Benefits

1. Sample Entire Video

For long videos, users can configure to sample throughout the video:

# For a 30-minute video, take 1 frame every 60 seconds
THUMBNAIL_GIF_START = 0
THUMBNAIL_GIF_DURATION = 1800    # 30 minutes
THUMBNAIL_GIF_FPS = 0.0167       # 1/60 = 1 frame per minute = 30 frames total

2. Reduce File Size

Lower frame rate for smaller GIF files:

THUMBNAIL_GIF_FPS = 0.5          # 1 frame every 2 seconds = smaller file

[mrjoshuap]

I like this idea! I am wondering if some of those values might be better calculated based on the length of the video? Are you thinking updating settings.py/local_setting.py to adjust?

[akulmehta]

@mrjoshuap The approach I suggested is the minimal changes which would be needed to reduce/customize the gif.

Calculating based on length of the video would be ideal - so you could for example say the gif should have 5 snapshots of the entire video and the code would automatically check the video length and then only put 5 screenshots from the video. I am new to the code base so not confident where to make these changes.

Note that this feature would also reduce load times and network loads.

[mrjoshuap]

Took your stuff as a base and made it a bit more robust; will need to be checked and tested, but should work.

[mrjoshuap]

Just a comment to see if I can get #1451 linked to this issue. I thought it was automatic as the commit was already made above?