Stabilizer Class Examples¶
Saving Stabilizer Class output with Live Audio Input¶
In this example code, we will merging the audio from a Audio Device (for e.g. Webcam inbuilt mic input) with Stabilized frames incoming from the Stabilizer Class (which is also using same Webcam video input through OpenCV), and save the final output as a compressed video file, all in real time:
New in v0.2.2
This example was added in v0.2.2
.
Example Assumptions
- You're running are Linux machine.
- You already have appropriate audio driver and software installed on your machine.
Identifying and Specifying sound card on different OS platforms
Windows OS users can use the dshow (DirectShow) to list audio input device which is the preferred option for Windows users. You can refer following steps to identify and specify your sound card:
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[OPTIONAL] Enable sound card(if disabled): First enable your Stereo Mix by opening the "Sound" window and select the "Recording" tab, then right click on the window and select "Show Disabled Devices" to toggle the Stereo Mix device visibility. Follow this post ➶ for more details.
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Identify Sound Card: Then, You can locate your soundcard using
dshow
as follows:c:\> ffmpeg -list_devices true -f dshow -i dummy ffmpeg version N-45279-g6b86dd5... --enable-runtime-cpudetect libavutil 51. 74.100 / 51. 74.100 libavcodec 54. 65.100 / 54. 65.100 libavformat 54. 31.100 / 54. 31.100 libavdevice 54. 3.100 / 54. 3.100 libavfilter 3. 19.102 / 3. 19.102 libswscale 2. 1.101 / 2. 1.101 libswresample 0. 16.100 / 0. 16.100 [dshow @ 03ACF580] DirectShow video devices [dshow @ 03ACF580] "Integrated Camera" [dshow @ 03ACF580] "USB2.0 Camera" [dshow @ 03ACF580] DirectShow audio devices [dshow @ 03ACF580] "Microphone (Realtek High Definition Audio)" [dshow @ 03ACF580] "Microphone (USB2.0 Camera)" dummy: Immediate exit requested
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Specify Sound Card: Then, you can specify your located soundcard in StreamGear as follows:
If audio still doesn't work then checkout this troubleshooting guide ➶ or reach us out on Gitter ➶ Community channel
Linux OS users can use the alsa to list input device to capture live audio input such as from a webcam. You can refer following steps to identify and specify your sound card:
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Identify Sound Card: To get the list of all installed cards on your machine, you can type
arecord -l
orarecord -L
(longer output).arecord -l **** List of CAPTURE Hardware Devices **** card 0: ICH5 [Intel ICH5], device 0: Intel ICH [Intel ICH5] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: ICH5 [Intel ICH5], device 1: Intel ICH - MIC ADC [Intel ICH5 - MIC ADC] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: ICH5 [Intel ICH5], device 2: Intel ICH - MIC2 ADC [Intel ICH5 - MIC2 ADC] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: ICH5 [Intel ICH5], device 3: Intel ICH - ADC2 [Intel ICH5 - ADC2] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: U0x46d0x809 [USB Device 0x46d:0x809], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0
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Specify Sound Card: Then, you can specify your located soundcard in WriteGear as follows:
The easiest thing to do is to reference sound card directly, namely "card 0" (Intel ICH5) and "card 1" (Microphone on the USB web cam), as
hw:0
orhw:1
If audio still doesn't work then reach us out on Gitter ➶ Community channel
MAC OS users can use the avfoundation to list input devices for grabbing audio from integrated iSight cameras as well as cameras connected via USB or FireWire. You can refer following steps to identify and specify your sound card on MacOS/OSX machines:
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Identify Sound Card: Then, You can locate your soundcard using
avfoundation
as follows:ffmpeg -f qtkit -list_devices true -i "" ffmpeg version N-45279-g6b86dd5... --enable-runtime-cpudetect libavutil 51. 74.100 / 51. 74.100 libavcodec 54. 65.100 / 54. 65.100 libavformat 54. 31.100 / 54. 31.100 libavdevice 54. 3.100 / 54. 3.100 libavfilter 3. 19.102 / 3. 19.102 libswscale 2. 1.101 / 2. 1.101 libswresample 0. 16.100 / 0. 16.100 [AVFoundation input device @ 0x7f8e2540ef20] AVFoundation video devices: [AVFoundation input device @ 0x7f8e2540ef20] [0] FaceTime HD camera (built-in) [AVFoundation input device @ 0x7f8e2540ef20] [1] Capture screen 0 [AVFoundation input device @ 0x7f8e2540ef20] AVFoundation audio devices: [AVFoundation input device @ 0x7f8e2540ef20] [0] Blackmagic Audio [AVFoundation input device @ 0x7f8e2540ef20] [1] Built-in Microphone
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Specify Sound Card: Then, you can specify your located soundcard in StreamGear as follows:
If audio still doesn't work then reach us out on Gitter ➶ Community channel
Make sure this -i
audio-source it compatible with provided video-source, otherwise you could encounter multiple errors or no output at all.
You MUST use -input_framerate
attribute to set exact value of input framerate when using external audio in Real-time Frames mode, otherwise audio delay will occur in output streams.
- Always keep this line above
-i
parameter!
Saving Stabilizer Class output with File Audio Input¶
In this example code, we will be directly merging the audio from a Video-File (to be stabilized) with its processed stabilized frames into a compressed video output in real time:
New in v0.2.4
This example was added in v0.2.4
.
Make sure this input video-file (to be stabilized) contains valid audio source, otherwise you could encounter multiple errors or no output at all.
You MUST use -input_framerate
attribute to set exact value of input framerate when using external audio in Real-time Frames mode, otherwise audio delay will occur in output streams.
Use -disable_force_termination
flag when video duration is too short(<60sec), otherwise WriteGear will not produce any valid output.