Creating Backup Stream from Image

A backup video stream from a static image provides a fallback when your primary source fails. The image can display a message like “Technical difficulties, please stand by” or similar service information. This approach is also useful for Emergency Alert Systems (EAS) to broadcast visual warnings.

Create Video File from Image

Video encoding is a resource-intensive task. To reduce CPU usage, pre-encode the image into short video files rather than encoding in real-time.

For smooth switching between primary and backup sources, the video codec must match your main stream. Create video files for each codec format you use (H.264, HEVC, etc.).

Check Primary Stream Format

Use ffprobe to analyze your primary stream:

ffprobe -hide_banner -v error -show_streams -show_format udp://239.255.1.1:1234

Look for these important parameters in the output:

• codec_name — video codec: h264, hevc, or mpeg2video
• width and height — video resolution, for example 1920 and 1080
• r_frame_rate — frame rate, for example 25/1 means 25 fps
• pix_fmt — pixel format, typically yuv420p
• profile — codec profile, for example high for H.264
• level — codec level, for example 40 means level 4.0

For a smooth switch between primary and backup sources, your backup video must match:

• Video codec
• Frame rate
• Resolution
• Pixel format

Create Video File

Use ffmpeg to convert a static image into a loopable video file. Set the parameters based on your primary stream analysis:

ffmpeg -loop 1 -i image.png -c:v libx264 -profile:v high -level 40 -s 1920x1080 -r 25 -pix_fmt yuv420p -t 10 /opt/ts/backup-h264.ts

Options explained:

• -loop 1 — loop the input image
• -i image.png — input image file (PNG, JPEG, or other format)
• -c:v libx264 — video codec (use libx265 for HEVC, mpeg2video for MPEG-2)
• -profile:v high — codec profile (match profile from ffprobe)
• -level 40 — codec level (match level from ffprobe)
• -s 1920x1080 — resolution (match width and height from ffprobe)
• -r 25 — frame rate (match r_frame_rate from ffprobe)
• -pix_fmt yuv420p — pixel format (match pix_fmt from ffprobe)
• -t 10 — duration in seconds
• /opt/ts/backup-h264.ts — output file in MPEG-TS format

For HEVC streams, change the encoder:

ffmpeg -loop 1 -i image.png -c:v libx265 -s 1920x1080 -r 25 -pix_fmt yuv420p -t 10 /opt/ts/backup-hevc.ts

For MPEG-2 streams:

ffmpeg -loop 1 -i image.png -c:v mpeg2video -b:v 5M -s 1920x1080 -r 25 -pix_fmt yuv420p -t 10 /opt/ts/backup-mpeg2.ts

Create Stream from Video File

Run FFmpeg to loop the video file and output it as a UDP stream:

ffmpeg -stream_loop -1 -re -i /opt/ts/backup-h264.ts -c copy -f mpegts 'udp://127.0.0.1:15001?pkt_size=1316'

Options explained:

• -stream_loop -1 — loop the file infinitely
• -re — read input at native frame rate
• -i /opt/ts/backup-h264.ts — input video file
• -c copy — copy streams without re-encoding
• -f mpegts — output format
• pkt_size=1316 — UDP packet size for MPEG-TS

Stream from File with Audio

The command above sends a video-only stream. Add sound when you broadcast the file, not when you create it. For example, a client can make a channel from a still image and a radio stream.

The audio source in this example is udp://127.0.0.1:14001. To receive an internet radio station and send it to UDP, see Receiving Radio Streams.

Use this command instead of the one above:

ffmpeg -stream_loop -1 -re -i /opt/ts/backup-h264.ts -i 'udp://127.0.0.1:14001' -map 0:v:0 -map 1:a:0 -c copy -f mpegts 'udp://127.0.0.1:15001?pkt_size=1316'

Options explained:

• -i 'udp://127.0.0.1:14001' — audio source, for example a radio stream. Use a different port than the output
• -map 0:v:0 — take video from the image file
• -map 1:a:0 — take the first audio stream from the audio source
• -c copy — copy video and audio without re-encoding

The other options are the same as in the command above.

The output address stays udp://127.0.0.1:15001, so the Astra setup below does not change.

To keep FFmpeg running, use the service below and add the audio input and -map options to ExecStart.

Running FFmpeg as a Service

To keep FFmpeg running continuously, set it up as a systemd service.

Create file /etc/systemd/system/backup-h264.service with the following content:

[Unit]
Description=Backup Video Stream from Image
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
ExecStart=/usr/bin/ffmpeg \
    -hide_banner -loglevel warning -nostats \
    -stream_loop -1 \
    -re \
    -i /opt/ts/backup-h264.ts \
    -c copy \
    -f mpegts 'udp://127.0.0.1:15001?pkt_size=1316'

Restart=always
RestartSec=5

StandardOutput=null
StandardError=journal

[Install]
WantedBy=multi-user.target

Replace in this file:

• File Name: use a relevant name instead of backup-h264.service if you have multiple backup streams
• Description: change to match your use case
• Input File: replace /opt/ts/backup-h264.ts with the actual path to your video file
• UDP Port: change 15001 to the UDP port you want to use. If you have multiple backup streams, use different ports.

After creating the service file, enable and start the service:

systemctl enable backup-h264
systemctl start backup-h264

Configure Astra

In the channel settings, add a second input source with the UDP address:

udp://127.0.0.1:15001

Astra will automatically switch to this backup stream when the primary source fails.