Title: Openai/69505485-7d60-8001-98fc-66951636b1d8 - freem

URL Source: https://freemwiki.com/index.php?mobileaction=toggle_view_mobile&title=Openai%2F69505485-7d60-8001-98fc-66951636b1d8

Markdown Content:
_This conversation was exported from ChatGPT_[[1]](https://freemwiki.com/index.php?mobileaction=toggle_view_mobile&title=Openai%2F69505485-7d60-8001-98fc-66951636b1d8#cite_note-1)

## gpt-5-2[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=1 "Edit section: gpt-5-2")

### User: I want to generate a 1MB mp4 file that Plex thinks is 90 minutes long[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=2 "Edit section: User: I want to generate a 1MB mp4 file that Plex thinks is 90 minutes long")

I want to generate a 1MB mp4 file that Plex thinks is 90 minutes long

### Assistant: You can do this by lying to the container metadata duration / timescale while keeping almost no actual frames.[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=3 "Edit section: Assistant: You can do this by lying to the container metadata duration / timescale while keeping almost no actual frames.")

You can do this by lying to the container metadata (duration / timescale) while keeping almost no actual frames. Plex relies heavily on MP4 container metadata, not actual frame count.

The most reliable approach is FFmpeg with a very low framerate + stretched duration metadata.

#### This produces a valid MP4 that Plex will see as ~90 minutes, while staying ~1 MB.[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=4 "Edit section: This produces a valid MP4 that Plex will see as ~90 minutes, while staying ~1 MB.")

ffmpeg -f lavfi -i color=c=black:s=16x16:r=0.000185 \
-c:v libx264 \
-pix_fmt yuv420p \
-t 5400 \
-movflags +faststart \
-profile:v baseline \
-level 1.0 \
-an \
90min.mp4

##### - 5400 seconds = 90 minutes[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=5 "Edit section: - 5400 seconds = 90 minutes")

*   0.000185 fps → only ~1 frame per 90 minutes
*   Tiny resolution (16×16)
*   No audio
*   Baseline profile = Plex friendly

Result:

*   ~500 KB – 1 MB
*   Plex reports 1h 30m duration
*   Plays instantly (or “ends” immediately depending on client)

#### If you want to keep exactly one frame and force duration metadata:[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=6 "Edit section: If you want to keep exactly one frame and force duration metadata:")

ffmpeg -loop 1 -i black.png \
-c:v libx264 \
-t 5400 \
-video_track_timescale 1000 \
-movflags +faststart \
-an \
90min.mp4

Where black.png is a single black pixel or tiny image.

This relies on MP4 timing metadata, which Plex respects.

#### Run:[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=7 "Edit section: Run:")

ffprobe 90min.mp4

Look for:

Duration: 01:30:00.00

If ffprobe sees it correctly, Plex almost certainly will.

#### - Plex does not validate frame density[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=8 "Edit section: - Plex does not validate frame density")

*   Plex trusts MP4 duration atom
*   Avoid MKV — Plex recalculates duration sometimes
*   No audio = smaller file and fewer playback issues

#### I can:[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=9 "Edit section: I can:")

*   Tune this to exactly 1.00 MB
*   Make Plex think it’s TV-episode length instead
*   Embed fake chapter markers
*   Make it seekable or non-seekable
*   Generate a version that never actually plays but still scans cleanly

Just say the word.

### [edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=10 "Edit section: User: Cam you comment that ffmpeg example to be able to modify it?")

Cam you comment that ffmpeg example to be able to modify it?

### Assistant: Absolutely — here’s the same FFmpeg command fully commented line-by-line, plus notes on what you can safely change.[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=11 "Edit section: Assistant: Absolutely — here’s the same FFmpeg command fully commented line-by-line, plus notes on what you can safely change.")

Absolutely — here’s the same FFmpeg command fully commented line-by-line, plus notes on what you can safely change.

#### Commented FFmpeg command (90-minute, ~1MB MP4)[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=12 "Edit section: Commented FFmpeg command (90-minute, ~1MB MP4)")

ffmpeg \
 -f lavfi \  # Use FFmpeg's built-in filter system as the input
 -i color=c=black:s=16x16:r=0.000185 \  # Generate a black video:
 # c=black → color
 # s=16x16 → resolution (smaller = smaller file)
 # r=0.000185 → frames per second (~1 frame per 90 min)

 -c:v libx264 \  # Encode video using H.264 (best Plex compatibility)
 -pix_fmt yuv420p \  # Pixel format Plex expects
 -t 5400 \  # Total duration in seconds (5400 = 90 minutes)

 -movflags +faststart \  # Move MP4 metadata to beginning of file (streaming-friendly)
 -profile:v baseline \  # Baseline profile for max device compatibility
 -level 1.0 \  # Very low H.264 level (fits tiny resolution)

 -an \  # Disable audio (saves space)
 90min.mp4 # Output filename

#### Common modifications (safe to tweak)[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=13 "Edit section: Common modifications (safe to tweak)")

##### ⏱ Change the duration[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=14 "Edit section: ⏱ Change the duration")

-t 3600 # 60 minutes
-t 2700 # 45 minutes
-t 10800 # 3 hours

Formula:

seconds = minutes × 60

##### 📐 Change resolution[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=15 "Edit section: 📐 Change resolution")

s=8x8 # even smaller
s=32x32 # still tiny
s=64x64 # larger but still small file

⚠️ Stick to multiples of 2 for H.264.
##### 🎞 Change “frame density” (size control)[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=16 "Edit section: 🎞 Change “frame density” (size control)")

r=0.0001 # fewer frames → smaller file
r=0.001 # more frames → larger file

Approximate relationship:

frames = duration × fps

For 90 minutes:

*   0.000185 ≈ 1 frame total
*   0.001 ≈ 5 frames
*   0.01 ≈ 54 frames

##### 📦 Targeting file size more precisely[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=17 "Edit section: 📦 Targeting file size more precisely")

Add a bitrate cap:

-b:v 1k # 1 kbps video bitrate

Example:

-b:v 1k -maxrate 1k -bufsize 2k

This lets you dial the file toward exact size targets (like exactly 1.00 MB).

#### Want audio but still tiny?[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=18 "Edit section: Want audio but still tiny?")

Add silent audio (Plex sometimes likes this):

-f lavfi -i anullsrc=channel_layout=mono:sample_rate=8000 \
-c:a aac -b:a 1k

(Add before output filename.)

#### Quick validation[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=19 "Edit section: Quick validation")

ffprobe 90min.mp4

Expected:

Duration: 01:30:00.00
Stream #0: Video: h264

#### TL;DR — knobs you’ll actually touch[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=20 "Edit section: TL;DR — knobs you’ll actually touch")

| Goal | Change | | ------------------ | -------------------------- | | Duration | -t | | File size | r=, s=, -b:v | | Plex compatibility | Keep libx264, yuv420p, MP4 | | Ultra-small | Lower r, lower s, no audio |

If you want, I can:

*   Calculate exact FPS for exactly N frames
*   Produce a 1.00 MB ± 1 KB version
*   Make Plex think it’s HDR / 4K / Dolby Vision
*   Make it scan as movie vs episode

Just tell me the constraints.

## References[edit](https://freemwiki.com/index.php?title=Openai/69505485-7d60-8001-98fc-66951636b1d8&action=edit&section=21 "Edit section: References")

1.   [↑](https://freemwiki.com/index.php?mobileaction=toggle_view_mobile&title=Openai%2F69505485-7d60-8001-98fc-66951636b1d8#cite_ref-1)["Generate fake 90min video"](https://chatgpt.com/share/69505485-7d60-8001-98fc-66951636b1d8). ChatGPT. Retrieved 2025-12-27.