Information & License

This manual was created by the streaming provider dos.gr and is freely available under the Creative Commons Attribution-ShareAlike 4.0 International license (CC BY-SA 4.0) . You can copy, modify, and republish it, provided that you cite the original source (dos.gr) and maintain the same license.

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→ Who we are

dos.gr is the first provider worldwide to publicly broadcast 1080p WebM/VP9 video via Icecast server, as evidenced by records in the Internet Archive:

June 2017: Icecast WebM Directory
June 2017: dos.gr live broadcast

Our team has been active since 1996, specializing in:
Live streaming: RTMP, HLS, Icecast, WebRTC, SRT
File formats: MP4, M3U8, WebM, FLV
Tools: VDO Panel, Wowza, OBS, FFmpeg, Nginx, Red5
ABR implementation, CDN usage, low latency
Kernel/sysctl/firewall/caching optimization

→ Services

We provide technical support and installation for:

RTMP / HLS / Icecast streaming
VDO Panel, Wowza, OBS, FFmpeg
Custom panels and custom server applications
Server optimization (BIOS, thermal, kernel-level)
Technical support in Greece and remotely (SSH, AnyDesk)
Website: dos.gr
Email: webm@dos.gr

→ Thank you for your interest

Thank you for reading this manual. We hope you find it useful in your effort to broadcast content openly, economically, and efficiently. → We would be particularly pleased if you visited our website and explored our services.

→ Who can use it & why

Intended for:
Radio stations wanting to show studio cams - Web TVs, small broadcasters - Online lessons, webinars - Surveillance cameras / science cams - Anyone with an idea without budget

→ Why WebM + Icecast?

No licenses/royalties (unlike Wowza, Flussonic, etc.)
Supported by all modern browsers
Minimal resource requirements
Excellent image quality with low bitrate
100% HTML5 – no Flash or plugins

→ Manual summary

This manual covers scheduled broadcasting of stored video files (not live) via Icecast v2. In a future manual, we will describe live streaming.

→ Requirements

You will need:

Icecast v2.4.4 (Centova Cast on Linux)
FFmpeg (7.1.1 on Linux for conversion)
FFmpeg static (6.1.1 on Windows for broadcasting)
Icecast can be local, on VPS, or at a provider, with or without a panel (e.g., Centova Cast).
Our broadcasting is done from Windows for practical reasons.

→ Advantages & Disadvantages

Conversion is done once, excellent quality with small file size
0% CPU usage during broadcast – no real-time transcoding
Stability, ideal for low-resource systems

High conversion time (e.g., 20 hours for 1-hour video with i9-9900K)
VP9 does not fully utilize threads
There are settings to speed up encoding (-row-mt, -tile-columns, -cpu-used)
But quality slightly decreases

→ Icecast server settings

To broadcast WebM/VP9 via Icecast v2, proper configuration of icecast.xml is required.

Below we provide a ready-made configuration file used in the production implementation of webm.win on Icecast v2 server (Centova Cast):

Download icewebm.txt file <
This file includes complete settings for:
SSL streaming (HTTPS)
video/webm mountpoint (/dos.webm)
Directory listings for Xiph and other directories
Proper settings for burst-size, queue, timeouts, logging, etc.

You can adapt the file according to your needs.
This implementation is fully functional and tested in real production conditions.

→ Icecast settings via Centova Cast panel

Below shows configuration of basic parameters via Centova Cast panel, such as:

Queue size: 12800000
Burst size: 2560000

Timeout values for Source/Client

These values exactly match the icecast.xml used in the production implementation on webm.win

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Limits settings

The image below shows basic restriction parameters, such as:

Maximum Bitrate (9000 Kbps) (set high to prevent Centova from auto-stopping this stream—setting lower doesn't matter, as long as it's not lower than your video bitrate)

Maximum listener number
Disk quota & mount point limit

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Mount Point settings

Settings for mount point /dos.webm on Icecast, such as:

MIME type: video/webm
Advertised bitrate: 2000 kbps
Stream name & description
Stream URL: rdst.win:59000/dos.webm

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→ Converting files to WebM/VP9

For converting files to WebM/VP9, we chose the 2-pass encoding method with ffmpeg, as tests showed it achieves the best image quality relative to file size.

Original videos were 4K, converted to 1920×1080 at constant 30fps.

All videos used the exact same command for uniformity during broadcast and playback across browsers and devices. Audio bitrate was set to 192 kbps for excellent quality without excessive size.

→ Example conversion command (2-pass VP9 WebM)

ffmpeg -y -i carlcox.mp4 -vf "scale=1920:1080,fps=30" -c:v libvpx-vp9 -b:v 2000k -g 15 -deadline good -cpu-used 0 -threads 16 -pass 1 -an -f webm -passlogfile ./ffmpeg2pass temp_pass1_output.webm

ffmpeg -y -i carlcox.mp4 -vf "scale=1920:1080,fps=30" -c:v libvpx-vp9 -b:v 2000k -g 15 -deadline good -cpu-used 0 -threads 16 -pass 2 -c:a libvorbis -b:a 192k -ar 44100 output_1080p_best_quality_2000k.webm

→ Explanation of key parameters

Parameter                     Description
-i carlcox.mp4                Original input file (MP4)
-vf "scale=1920:1080,fps=30"  Output resolution and frame rate
-c:v libvpx-vp9               Video codec VP9
-b:v 2000k                    Video bitrate 2000 kbps
-g 15                         Keyframe distance (GOP)—ideal for stable seeking
-deadline good                Balance between quality and speed
-cpu-used 0                   Maximum quality (slower encoding)
-threads 16                   Using 16 CPU threads
-pass 1 / -pass 2             First and second pass for optimized quality
-an                           Disable audio in the first pass (not needed)
-c:a libvorbis                Vorbis codec for audio
-b:a 192k                     Audio bitrate 192 kbps
-ar 44100                     Audio frequency 44.1kHz
-f webm                       Output format WebM
-passlogfile                  File storing 1st pass information

→ Playlist creation & scheduled broadcast

Broadcasting is done via Windows, using a simple input.txt playlist and ffmpeg command:

-re -f concat -safe 0 -i C:/Users/lyk/Desktop/ffmpegyag/videos/1080p/30fps/input.txt -c copy -f webm -cluster_size_limit 2M -cluster_time_limit 5100 -content_type video/webm icecast://source:topassmou123@rdst.win:9000/dos.webm

The file input.txt contains the paths of all .webm files to be played sequentially. Example:

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For greater convenience and reliability, the broadcast is run as a Windows service via FireDaemon, enabling it to start automatically, restart in case of failure, and operate in the background:

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In this way, CPU usage during broadcasting remains at 0%, since no re-encoding takes place — the content is already fully prepared for streaming.

The same process can be just as easily implemented on Linux, using a cron job or a systemd service script.

Comment:
It would be especially helpful if the developers of Centova Cast added built-in support for .webm playlists or playback of files via ffmpeg concat. This would allow for automatic broadcasting of scheduled WebM/VP9 content directly from the panel — just like it already works with MP3.

→ Final Notes
This manual provides a step-by-step guide for the entire process:
from file conversion and Icecast configuration to scheduled broadcasting in a production environment.

From this point on... explore a little on your own!
The internet is full of examples, technical articles, and of course... DeepSeek/ChatGPT, which can help you experiment further — especially with custom setups, automation, or HTML integration.

If you need professional support, we’re here:
dos.gr | webm@dos.gr

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→ Archived at 26.May.2025: Internet Archive (Wayback Machine) - Zenodo (DOI) - Licensed under CC BY-SA 4.0