Introduction

Moonfire NVR is an open-source security camera network video recorder, started by Scott Lamb slamb@slamb.org. Currently it is basic: it saves H.264-over-RTSP streams from IP cameras to disk as .mp4 files and provides a simple HTTP interface for listing and viewing fixed-length segments of video. It does not decode, analyze, or re-encode video frames, so it requires little CPU. It handles six 720p/15fps streams on a Raspberry Pi 2, using roughly 5% of the machine's total CPU.

This is version 0.1, the initial release. Until version 1.0, there will be no compatibility guarantees: configuration and storage formats may change from version to version.

I hope to add features such as salient motion detection. It's way too early to make promises, but it seems possible to build a full-featured hobbyist-oriented multi-camera NVR that requires nothing but a cheap machine with a big hard drive. I welcome help; see Getting help and getting involved below. There are many exciting techniques we could use to make this possible:

• avoiding CPU-intensive H.264 encoding in favor of simply continuing to use the camera's already-encoded video streams. Cheap IP cameras these days provide pre-encoded H.264 streams in both "main" (full-sized) and "sub" (lower resolution, compression quality, and/or frame rate) varieties. The "sub" stream is more suitable for fast computer vision work as well as remote/mobile streaming. Disk space these days is quite cheap (with 3 TB drives costing about $100), so we can afford to keep many camera-months of both streams on disk.
• decoding and analyzing only select "key" video frames (see wikipedia.
• off-loading expensive work to a GPU. Even the Raspberry Pi has a surprisingly powerful GPU.
• using HTTP Live Streaming rather than requiring custom browser plug-ins.
• taking advantage of cameras' built-in motion detection. This is the most obvious way to reduce motion detection CPU. It's a last resort because these cheap cameras' proprietary algorithms are awful compared to those described on changedetection.net. Cameras have high false-positive and false-negative rates, are hard to experiment with (as opposed to rerunning against saved video files), and don't provide any information beyond if motion exceeded the threshold or not.

Downloading

See the github page (in case you're not reading this text there already). You can download the bleeding edge version from the commandline via git:

$ git clone https://github.com/scottlamb/moonfire-nvr.git

Building from source

There are no binary packages of Moonfire NVR available yet, so it must be built from source. It requires several packages to build:

• CMake version 3.1.0 or higher.
• a C++11 compiler, such as gcc 4.7 or higher.
• ffmpeg, including libavutil, libavcodec (to inspect H.264 frames), and libavformat (to connect to RTSP servers and write .mp4 files). Note ffmpeg versions older than 55.1.101, along with all versions of the competing project libav, does not support socket timeouts for RTSP. For reliable reconnections on error, it's strongly recommended to use ffmpeg >= 55.1.101.
• libevent 2.x, for the built-in HTTP server. (This might be replaced with the more full-featured nghttp2 in the future.)
• protocol buffers, currently just for the configuration file.
• gflags, for commandline flag parsing.
• glog, for debug logging.
• gperftools, for debugging.
• googletest, for automated testing. This will be automatically downloaded during the build process, so it's not necessary to install it beforehand.
• re2, for parsing with regular expressions.

On Ubuntu 15.10 or Raspbian Jessie, the following command will install all pre-requisites (see also the Build-Depends field in debian/control):

$ sudo apt-get install \
               build-essential \
               cmake \
               libprotobuf-dev \
               libavcodec-dev \
               libavformat-dev \
               libavutil-dev \
               libevent-dev \
               libgflags-dev \
               libgoogle-glog-dev \
               libgoogle-perftools-dev \
               libre2-dev \
               pkgconf \
               protobuf-compiler

Once prerequisites are installed, Moonfire NVR can be built as follows:

$ mkdir build
$ cd build
$ cmake ..
$ make
$ sudo make install

Alternatively, you can prepare a .deb package:

$ sudo apt-get install devscripts dh-systemd
$ debuild -us -uc

Configuration

Moonfire NVR expects a configuration file /etc/moonfire-nvr.conf (overridable with the --config argument). Currently this file should contain a text-format moonfire_nvr.Config protocol buffer message; see src/config.protodevel which describes the meaning of fields. The general syntax is as in the example below: field: value for simple fields, or (field < ... >) for "message" fields. It supports line-based comments starting with #.

base_path: "/var/lib/moonfire_nvr"
rotate_sec: 600
http_port: 8080

camera <
  short_name: "back_west"
  host: "192.168.1.101:554"
  user: "admin"
  password: "12345"
  main_rtsp_path: "/Streaming/Channels/1"
  sub_rtsp_path: "/Streaming/Channels/2"
  retain_bytes: 52428800  # 50 MiB
>
camera <
  short_name: "back_east"
  host: "192.168.1.102:554"
  user: "admin"
  password: "12345"
  main_rtsp_path: "/Streaming/Channels/1"
  sub_rtsp_path: "/Streaming/Channels/2"
  retain_bytes: 52428800  # 50 MiB
>

The example configuration above does the following:

• streams the main_rtsp_path from both cameras, reconnecting on errors, and writing 10-minute segments of video to subdirectories of /var/lib/surveillance/. (The sub_rtsp_path field is not used yet.)
• deletes old files to stay within the 50 MiB limit for each camera, excluding the video file currently being written.
• writes human-readable debug logs to /tmp/moonfire_nvr.INFO.
• runs an HTTP server on the port 8080 (try http://localhost:8080/ which allows streaming the video. Note: Moonfire NVR does not yet support authentication or SSL, so this webserver should not be directly exposed to the Internet.

When configuring Moonfire NVR, it may be helpful to replicate its basic functionality with the ffmpeg commandline tool. The command below is roughly equivalent to the configuration for back_west above.

$ ffmpeg \
      -i "rtsp://admin:12345@192.168.1.101:554/Streaming/Channels/1" \
      -c copy \
      -map 0:0 \
      -flags:v +global_header \
      -bsf:v dump_extra \
      -f segment \
      -segment_time 600 \
      -use_strftime 1 \
      -segment_format mp4 \
      %Y%m%d%H%M%S-back_west.mp4

Installation

Moonfire NVR should be run under a dedicated user. This user should own the base_path directory mentioned in the configuration file. Because video is served through an HTTP interface, there's no need for any other user to access the files.

$ sudo addgroup --system moonfire-nvr
$ sudo adduser --system moonfire-nvr --group moonfire-nvr
$ sudo mkdir /var/lib/moonfire_nvr
$ sudo chown moonfire-nvr:moonfire-nvr /var/lib/moonfire_nvr
$ sudo chmod 700 /var/lib/moonfire_nvr

It can be run as a systemd service. Create /etc/systemd/system/moonfire-nvr.service:

[Unit]
Description=Moonfire NVR
After=network-online.target

[Service]
ExecStart=/usr/local/bin/moonfire_nvr
Type=simple
User=moonfire-nvr
Nice=-20
Restart=on-abnormal
CPUAccounting=true
MemoryAccounting=true
BlockIOAccounting=true

[Install]
WantedBy=multi-user.target

Complete the installation through systemctl commands:

$ sudo systemctl daemon-reload
$ sudo systemctl start moonfire-nvr.service
$ sudo systemctl status moonfire-nvr.service
$ sudo systemctl enable moonfire-nvr.service

See the systemd documentation for more information. The manual pages for systemd.service and systemctl may be of particular interest.

While Moonfire NVR is running, logs will be written to /tmp/moonfire_nvr.INFO.

Getting help and getting involved

Please email the moonfire-nvr-users mailing list with questions, bug reports, feature requests, or just to say you love/hate the software and why.

I'd welcome help with testing, development (in C++, JavaScript, and HTML), user interface/graphic design, and documentation. Please email the mailing list if interested. Patches are welcome, but I encourage you to discuss large changes on the mailing list first to save effort.

C++ code should be written using C++11 features, should follow the Google C++ style guide for consistency, and should be automatically tested where practical. But don't worry about this too much; I'm much happier to work with you to refine a rough draft patch than never see your contribution at all!

License

This file is part of Moonfire NVR, a security camera digital video recorder. Copyright (C) 2016 Scott Lamb slamb@slamb.org

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

In addition, as a special exception, the copyright holders give permission to link the code of portions of this program with the OpenSSL library under certain conditions as described in each individual source file, and distribute linked combinations including the two.

You must obey the GNU General Public License in all respects for all of the code used other than OpenSSL. If you modify file(s) with this exception, you may extend this exception to your version of the file(s), but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. If you delete this exception statement from all source files in the program, then also delete it here.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.