设备枚举

查看设备列表

$ ffmpeg -hide_banner -devices

Devices:
D. = Demuxing supported
.E = Muxing supported
 --
D avfoundation AVFoundation input device
D lavfi  Libavfilter virtual input device
 E sdl,sdl2 SDL2 output device

可以看到输入设备有：avfoundation，lavfi
输出设备有：sdl
``
设备采集举例：

$  ffmpeg -f avfoundation -list_devices true -i " "

看到了 如下设备

[AVFoundation input device @ 0x7fac75c048c0] AVFoundation video devices:
[AVFoundation input device @ 0x7fac75c048c0] [0] FaceTime高清摄像头（内建）
[AVFoundation input device @ 0x7fac75c048c0] [1] Capture screen 0
[AVFoundation input device @ 0x7fac75c048c0] AVFoundation audio devices:
[AVFoundation input device @ 0x7fac75c048c0] [0] Built-in Microphone

采集摄像头

采集内置摄像头

$ ffmpeg -f avfoundation -i  "FaceTime高清摄像头" out.mp4
//或者使用索引号 0 来代替摄像头设备名称
ffmpeg -f avfoundation -i  0 out.mp4

[avfoundation @ 0x7fbf16808200] Selected framerate (29.970030) is not supported by the device.
[avfoundation @ 0x7fbf16808200] Supported modes:
[avfoundation @ 0x7fbf16808200]   640x480@[30.000030 30.000030]fps
[avfoundation @ 0x7fbf16808200]   640x480@[29.000049 29.000049]fps
[avfoundation @ 0x7fbf16808200]   640x480@[28.000067 28.000067]fps
[avfoundation @ 0x7fbf16808200]   640x480@[27.000027 27.000027]fps
[avfoundation @ 0x7fbf16808200]   640x480@[26.000026 26.000026]fps
[avfoundation @ 0x7fbf16808200]   640x480@[25.000000 25.000000]fps

日志告诉我们 Selected framerate (29.970030) is not supported by the device ，默认的framerate 不被设备支持，下面也给出了支持的分辨率和framerate
所以我们要改一下命令,选取第一个吧 640x480@[30.000030 30.000030]fps

ffmpeg -f avfoundation -video_size 640x480 -framerate 30 -i  "FaceTime高清摄像头" out.mp4

把摄像头和麦克风的数据存到一个文件里，使用命令：

ffmpeg -f avfoundation -video_size 640x480 -framerate 30 -video_device_index 0 -i ":0" out.mp4
//或者
ffmpeg -f avfoundation -video_size 640x480 -framerate 30 -i "0:0"  out.mp4

播放录制的视频数据

ffplay out.mp4

采集桌面

ffmpeg -f avfoundation -i "Capture screen 0" -r:v 30 screen.mp4
//或者使用索引号1 来代替屏幕设备名称
ffmpeg -f avfoundation -i 1 -r:v 30 screen.mp4

播放采集到的桌面数据

ffplay screen.mp4

参数"Capture screen 0"指定了输入设备，我们也可以将桌面图像带上鼠标一起录制下来，加上参数-capture_cursor

ffmpeg -f avfoundation -capture-cursor 1 -i "Capture screen 0" -r:v 30 screen.mp4

然后播放screen.mp4验证。ffplay screen.mp4

--完--