Editing Openai/69505485-7d60-8001-98fc-66951636b1d8


{{DISPLAYTITLE:Generate fake 90min video}}

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== gpt-5-2 ==
=== 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. ===
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. ====

<syntaxhighlight lang="bash">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

</syntaxhighlight>

===== - 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: ====

<syntaxhighlight lang="bash">ffmpeg -loop 1 -i black.png \
-c:v libx264 \
-t 5400 \
-video_track_timescale 1000 \
-movflags +faststart \
-an \
90min.mp4

</syntaxhighlight>

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

This relies on MP4 timing metadata, which Plex respects.

==== Run: ====

<syntaxhighlight lang="bash">ffprobe 90min.mp4

</syntaxhighlight>

Look for:

<syntaxhighlight>Duration: 01:30:00.00

</syntaxhighlight>

If ffprobe sees it correctly, Plex almost certainly will.

==== - 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: ====
* 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.

=== 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. ===
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) ====

<syntaxhighlight lang="bash">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

</syntaxhighlight>

==== Common modifications (safe to tweak) ====

===== ⏱ Change the duration =====

<syntaxhighlight lang="bash">-t 3600   # 60 minutes
-t 2700   # 45 minutes
-t 10800  # 3 hours

</syntaxhighlight>

Formula:

<syntaxhighlight>seconds = minutes × 60

</syntaxhighlight>

===== 📐 Change resolution =====

<syntaxhighlight lang="bash">s=8x8     # even smaller
s=32x32   # still tiny
s=64x64   # larger but still small file

</syntaxhighlight>

: ⚠️ Stick to multiples of 2 for H.264.

===== 🎞 Change “frame density” (size control) =====

<syntaxhighlight lang="bash">r=0.0001   # fewer frames → smaller file
r=0.001    # more frames → larger file

</syntaxhighlight>

Approximate relationship:

<syntaxhighlight>frames = duration × fps

</syntaxhighlight>

For 90 minutes:
* 0.000185 ≈ 1 frame total
* 0.001 ≈ 5 frames
* 0.01 ≈ 54 frames

===== 📦 Targeting file size more precisely =====

Add a bitrate cap:

<syntaxhighlight lang="bash">-b:v 1k    # 1 kbps video bitrate

</syntaxhighlight>

Example:

<syntaxhighlight lang="bash">-b:v 1k -maxrate 1k -bufsize 2k

</syntaxhighlight>

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

==== Want audio but still tiny? ====

Add silent audio (Plex sometimes likes this):

<syntaxhighlight lang="bash">-f lavfi -i anullsrc=channel_layout=mono:sample_rate=8000 \
-c:a aac -b:a 1k

</syntaxhighlight>

(Add before output filename.)

==== Quick validation ====

<syntaxhighlight lang="bash">ffprobe 90min.mp4

</syntaxhighlight>

Expected:

<syntaxhighlight>Duration: 01:30:00.00
Stream #0: Video: h264

</syntaxhighlight>

==== 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 ==
<references />


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