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Overview

BloodCat includes a bash script play.sh that automatically opens all discovered RTSP streams in individual viewing windows using ffplay.

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Requirements

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FFmpeg Installation

The viewer requires ffplay, which is part of the FFmpeg package.
1

Check if ffplay is installed

ffplay -version
2

Install FFmpeg (if needed)

Ubuntu/Debian:
sudo apt update && sudo apt install ffmpeg
macOS:
brew install ffmpeg
Arch Linux:
sudo pacman -S ffmpeg
The script automatically checks for ffplay and displays installation instructions if it’s missing (see play.sh:11-17).

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Usage

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Basic Usage

After running BloodCat and discovering cameras: 
./play.sh
This will:
  1. Read all RTSP URLs from ./data/ipcam.info
  2. Open each stream in a separate ffplay window
  3. Display streams in a grid layout

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What Happens

From play.sh:27-37, the script: 
while IFS= read -r line
do
    # Skip empty lines or invalid RTSP URLs
    if [[ -z "$line" || ! "$line" =~ ^rtsp:// ]]; then
        continue
    fi

    echo "Playing stream: $line"
    ffplay -rtsp_transport tcp -x 420 -y 340 "$line" &
    sleep 1
done < "$FILE"

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FFplay Command Parameters

The actual command used to play each stream: 
ffplay -rtsp_transport tcp -x 420 -y 340 "rtsp://username:password@ip:port/path" &

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Parameter Breakdown

Forces RTSP to use TCP instead of UDP for more reliable streaming through firewalls and NAT.
Sets the video window width to 420 pixels.
Sets the video window height to 340 pixels.
Runs the ffplay process in the background, allowing multiple streams to play simultaneously.

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Viewing Grid Layout

Each stream opens in a window sized 420×340 pixels. This size is chosen to allow multiple camera feeds to be arranged in a grid on your screen without overlapping.
For example, on a 1920×1080 display, you can comfortably view approximately 12 camera feeds (4 columns × 3 rows) simultaneously.

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Example Layout

┌─────────┬─────────┬─────────┬─────────┐
│ Camera 1│ Camera 2│ Camera 3│ Camera 4│
│ 420x340 │ 420x340 │ 420x340 │ 420x340 │
├─────────┼─────────┼─────────┼─────────┤
│ Camera 5│ Camera 6│ Camera 7│ Camera 8│
│ 420x340 │ 420x340 │ 420x340 │ 420x340 │
└─────────┴─────────┴─────────┴─────────┘

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Error Handling

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File Not Found

From play.sh:20-24, the script checks if the output file exists: 
FILE="./data/ipcam.info"
if [ ! -f "$FILE" ]; then
    echo "File $FILE not found!"
    exit 1
fi
You must run BloodCat and successfully discover at least one camera before using the viewer.

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Invalid URLs

The script automatically skips:
  • Empty lines
  • Lines that don’t start with rtsp://
This prevents errors from malformed entries in the output file.

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Stopping the Viewer

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Stop All Streams

Since all ffplay instances run in the background, you can stop them all at once: 
pkill ffplay

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Stop Individual Stream

Close individual stream windows by:
  • Clicking the window close button
  • Pressing ESC or Q while the window is focused

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Advanced Usage

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Custom Window Size

You can modify the window dimensions by editing play.sh:35: 
ffplay -rtsp_transport tcp -x 640 -y 480 "$line" &

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UDP Transport

If you prefer UDP (faster but less reliable): 
ffplay -rtsp_transport udp -x 420 -y 340 "$line" &

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Full Screen Mode

To play a single stream in fullscreen: 
ffplay -rtsp_transport tcp -fs "rtsp://admin:[email protected]:554/live.sdp"
Press F while an ffplay window is focused to toggle fullscreen mode.

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