Difference between revisions of "Audio Switching"
| Line 22: | Line 22: | ||
The "auto", "mic" and "EC" (video) modes can also be selected from Menu 2 of the Touchscreen. | The "auto", "mic" and "EC" (video) modes can also be selected from Menu 2 of the Touchscreen. | ||
| + | |||
| + | ===Identification of Audio Devices=== | ||
| + | |||
| + | Audio devices are identified as being Microphone Dongles or EasyCaps by analysing the response to the Linux command "arecord -l". | ||
| + | |||
| + | If the response includes any of the following strings (case sensitive) , the device is classed as a USB Microphone Dongle: | ||
| + | |||
| + | USB Audio Device | ||
| + | USB AUDIO | ||
| + | Head | ||
| + | Sound Device | ||
| + | |||
| + | If the response includes any of the following strings, the device is classed as a video capture device: | ||
| + | |||
| + | usbtv | ||
| + | U0x534d0x21 | ||
| + | DVC90 | ||
| + | Cx231xxAudio | ||
| + | STK1160 | ||
| + | U0xeb1a0x2861 | ||
| + | AV TO USB | ||
| + | |||
| + | Note that inclusion in this list does not mean that the Portsdown will work with the device for video capture. All it means is that it can capture audio from it; in particular, the DVC90 and Cx231xxAudio devices will not work for video capture (yet). | ||
| + | |||
| + | If you want an entry added to either of these lists (which each appear twice between lines 70 and 100 in the file scripts/a.sh) please post full details on the BATC Forum. | ||
Revision as of 19:23, 25 July 2017
The capability to transmit or stream sound from either the video capture device (EasyCap) or a microphone connected through a cheap USB dongle was overhauled and further developed in software 201707221.
In the Console, System Setup, Audio Input menu there are 5 options: auto, mic, video, bleeps and no_audio. The switching behaviour is as follows:
1 If "no_audio" is selected, no audio stream is generated.
2 If "bleeps" is selected, mono bleeps are transmitted.
3 If neither an EasyCap or USB Sound Dongle is detected (see below), no audio channel is generated, unless the option for "bleeps" has been requested. In which case "bleeps" are generated.
4 In "auto" mode:
If both an EasyCap and a USB Sound Dongle are detected, the video source is checked. If video from the Pi Cam is selected, mono audio from the USB Sound Dongle is transmitted. If the EasyCap is selected for video, stereo audio from the EasyCap is transmitted.
If only a USB Sound Dongle is detected, mono audio from the USB Sound Dongle is transmitted.
If only an EasyCap is detected, stereo audio from the EasyCap is transmitted.
5 In "mic" mode, if a USB Sound Dongle is detected, mono audio from the USB Sound Dongle is transmitted. If no USB Sound Dongle is detected, but an EasyCap is, stereo audio from the EasyCap is transmitted.
6. In "video" mode, if an EasyCap is detected, stereo audio from the EasyCap is transmitted. If no EasyCap is detected, but a USB Sound Dongle is, mono audio from the USB Sound Dongle is transmitted.
The "auto", "mic" and "EC" (video) modes can also be selected from Menu 2 of the Touchscreen.
Identification of Audio Devices
Audio devices are identified as being Microphone Dongles or EasyCaps by analysing the response to the Linux command "arecord -l".
If the response includes any of the following strings (case sensitive) , the device is classed as a USB Microphone Dongle:
USB Audio Device USB AUDIO Head Sound Device
If the response includes any of the following strings, the device is classed as a video capture device:
usbtv U0x534d0x21 DVC90 Cx231xxAudio STK1160 U0xeb1a0x2861 AV TO USB
Note that inclusion in this list does not mean that the Portsdown will work with the device for video capture. All it means is that it can capture audio from it; in particular, the DVC90 and Cx231xxAudio devices will not work for video capture (yet).
If you want an entry added to either of these lists (which each appear twice between lines 70 and 100 in the file scripts/a.sh) please post full details on the BATC Forum.