- Capture video from Raspberry Pi Camera (up to 720p) and encode it to H.264 using hardware encoder
- Capture audio from USB microphone via ALSA and encode it to AAC-LC using libavcodec (FFmpeg)
- Record to an MPEG-TS file
- Generate files for HTTP Live Streaming with optional encryption
- If USB microphone is not available, it only records the video
- Only 30 FPS is supported
Time from real motion to playback on Strobe Media Player over RTMP:
| Video bitrate | Minimum latency |
|---|---|
| 300 Kbps | 0.3 sec |
| 500 Kbps | 0.6 sec |
| 1 Mbps | 0.8 sec |
| 2 Mbps | 1.0 sec |
| 3 Mbps | 1.3 sec |
Tested with:
- Video: 1280x720, 30 fps, GOP size 30
- Audio: 48 Khz mono, 40 Kbps
- RTMP Server: node-rtsp-rtmp-server
- Client: Flash Player 14,0,0,145 on Firefox 31.0 for Mac, using test/strobe_media_playback.html
- Network: Wi-Fi network created by a USB dongle attached to Raspberry Pi
- Raspberry Pi
- Raspberry Pi Camera Board
- USB microphone (see Recommended hardware)
- Raspbian
- Arch Linux
See INSTALL.md.
picam command continuously reads video from Raspberry Pi Camera and audio from ALSA.
$ ./picam
video_width=1280
video_height=720
video_fps=30.0
gop_size=30
video_bitrate=2000000
alsa_dev=hw:0,0
audio_sample_rate=48000
audio_bitrate=40000
audio_volume_multiply=1.000000
is_hlsout_enabled=0
is_hls_encryption_enabled=0
hls_encryption_key_uri=stream.key
hls_encryption_key=0x75b0a81de17487c88a47507a7e1fdf73
hls_encryption_iv=0x000102030405060708090a0b0c0d0e0f
hls_output_dir=/run/shm/video
rtsp_enabled=0
rtsp_video_control_path=/tmp/node_rtsp_rtmp_videoControl
rtsp_audio_control_path=/tmp/node_rtsp_rtmp_audioControl
rtsp_video_data_path=/tmp/node_rtsp_rtmp_videoData
rtsp_audio_data_path=/tmp/node_rtsp_rtmp_audioData
tcp_enabled=0
tcp_output_dest=
auto_exposure_enabled=0
exposure_night_y_threshold=40
exposure_auto_y_threshold=50
is_preview_enabled=0
record_buffer_keyframes=5
state_dir=state
hooks_dir=hooks
exposure mode: auto
................................ 31.46 fps k=1
.............................. 30.49 fps k=2
.............................. 30.55 fps k=3
To start recording, create a file named hooks/start_record while picam command is running.
$ touch hooks/start_record
You will see start rec in the picam command output.
To stop recording, create a file named hooks/stop_record.
$ touch hooks/stop_record
The recorded MPEG-TS file is in rec/archive/ directory.
To convert MPEG-TS to MP4, run:
$ ffmpeg -i test.ts -c:v copy -c:a copy -bsf:a aac_adtstoasc test.mp4
To mute microphone temporarily, create a file named hooks/mute.
$ touch hooks/mute
To unmute microphone, create a file named hooks/unmute.
$ touch hooks/unmute
$ ./picam --help
picam version 1.0.0
Usage: picam [options]
Options:
[video]
-w, --width Width in pixels (default: 1280)
-h, --height Height in pixels (default: 720)
-v, --videobitrate Video bit rate (default: 2000000)
-g, --gopsize GOP size (default: 30)
[audio]
-r, --samplerate Audio sample rate (default: 48000)
-a, --audiobitrate Audio bit rate (default: 40000)
--alsadev <dev> ALSA microphone device (default: hw:0,0)
--volume <num> Amplify audio by multiplying the volume by <num>
(default: 1.0)
[HTTP Live Streaming (HLS)]
-o, --hlsdir <dir> Generate HTTP Live Streaming files in <dir>
--hlsenc Enable HLS encryption
--hlsenckeyuri <uri> Set HLS encryption key URI (default: stream.key)
--hlsenckey <hex> Set HLS encryption key in hex string
(default: 75b0a81de17487c88a47507a7e1fdf73)
--hlsenciv <hex> Set HLS encryption IV in hex string
(default: 000102030405060708090a0b0c0d0e0f)
[output for node-rtsp-rtmp-server]
--rtspout Enable output for node-rtsp-rtmp-server
--rtspvideocontrol <path> Set video control socket path
(default: /tmp/node_rtsp_rtmp_videoControl)
--rtspaudiocontrol <path> Set audio control socket path
(default: /tmp/node_rtsp_rtmp_audioControl)
--rtspvideodata <path> Set video data socket path
(default: /tmp/node_rtsp_rtmp_videoData)
--rtspaudiodata <path> Set audio data socket path
(default: /tmp/node_rtsp_rtmp_audioData)
[MPEG-TS output via TCP]
--tcpout <url> Enable TCP output to <url>
(e.g. --tcpout tcp://127.0.0.1:8181)
[camera]
--autoexposure Enable automatic changing of exposure
--expnight <num> Change the exposure to night mode if the average
value of Y (brightness) is <= <num> while in
daylight mode (default: 40)
--expday <num> Change the exposure to daylight mode if the average
value of Y (brightness) is >= <num> while in
night mode (default: 50)
-p, --preview Display a preview window for video
[misc]
--recordbuf <num> Start recording from <num> keyframes ago
(default: 5)
--statedir <dir> Set state dir (default: state)
--hooksdir <dir> Set hooks dir (default: hooks)
-q, --quiet Turn off most of the log messages
--help Print this help
HTTP Live Streaming is disabled by default. To enable HTTP Live Streaming and generate files in /run/shm/hls, run:
$ ./picam -o /run/shm/hls
Optionally you can enable encryption for HTTP Live Streaming. We will use the following settings as an example.
- HTTP Live Streaming output directory: /run/shm/hls/
- Encryption key: 0xf0f1f2f3f4f5f6f7f8f9fafbfcfdfeff
- Encryption IV: 0x000102030405060708090a0b0c0d0e0f
- Encryption key file: enc.key
First you have to create a file named "enc.key" which contains 16-byte encryption key. To create such file, run:
$ echo -n $'\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff' > enc.key
Put enc.key in /run/shm/hls/ directory. Then, run picam with the following options:
$ ./picam -o /run/shm/hls --hlsenc --hlsenckeyuri enc.key \
--hlsenckey f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff \
--hlsenciv 000102030405060708090a0b0c0d0e0f
You can watch the HTTP Live Streaming by accessing /run/shm/hls/index.m3u8 via HTTP or HTTPS with QuickTime Player.
To use picam with nginx-rtmp-module, add the following lines to nginx.conf:
rtmp {
server {
listen 1935;
chunk_size 4000;
application webcam {
live on;
exec_static /path/to/ffmpeg -i tcp://127.0.0.1:8181?listen
-c:v copy -ar 44100 -ab 40000
-f flv rtmp://localhost:1935/webcam/mystream;
}
}
}
Note that /path/to/ffmpeg should be replaced with the actual absolute path to ffmpeg command.
Start nginx server, then run:
$ ./picam --tcpout tcp://127.0.0.1:8181
You can access your live stream at rtmp://YOUR_RASPBERRYPI_IP/webcam/mystream.
Any cheap USB microphone should work as long as it is supported by ALSA. I have tested this program with the combination of:
- USB to 3.5mm audio adapter: PLANEX PL-US35AP
- Microphone: ELECOM MS-STM95
LGPL v2.1, as some parts of FFmpeg source is included.