将原始OpenCV图像传输到FFmpeg-PiperawOpenCVimagestoFFmpeg

30  

Took a bunch of fiddling but I figured it out using the FFmpeg rawvideo demuxer:

采取了一堆摆弄，但我发现使用FFmpeg rawvideo demuxer：

python capture.py | ffmpeg -f rawvideo -pixel_format bgr24 -video_size 640x480 -framerate 30 -i - foo.avi

Since there is no header in raw video specifying the assumed video parameters, the user must specify them in order to be able to decode the data correctly:

由于原始视频中没有标题指定假定的视频参数，因此用户必须指定它们才能正确解码数据：

• -framerate Set input video frame rate. Default value is 25.
• -framerate设置输入视频帧速率。默认值为25。
• -pixel_format Set the input video pixel format. Default value is yuv420p.
• -pixel_format设置输入视频像素格式。默认值为yuv420p。
• -video_size Set the input video size. There is no default, so this value must be specified explicitly.
• -video_size设置输入视频大小。没有默认值，因此必须明确指定此值。

And here's a little something extra for the power users. Same thing but using VLC to stream the live output to the web, Flash format:

对于高级用户来说，这里有一些额外的东西。同样的事情，但使用VLC将实时输出流式传输到Web，Flash格式：

python capture.py | cvlc --demux=rawvideo --rawvid-fps=30 --rawvid-#transcode{vcodec=h264,vb=200,fps=30,

Edit: Create a webm stream using ffmpeg and ffserver

编辑：使用ffmpeg和ffserver创建webm流

python capture.py | ffmpeg -f rawvideo -pixel_format rgb24 -video_size 640x480 -framerate 25 -i - http://localhost:8090/feed1.ffm

1  

Took me an hour to figure out that by default, windows pipes are not binary. This causes some bytes (specifically newlines) to be modified/omitted, and the resulting video is slowly shifting because the frame size is not constant.

花了我一个小时来弄清楚默认情况下，Windows管道不是二进制的。这导致一些字节（特别是换行符）被修改/省略，并且由于帧大小不是恒定的，所得到的视频正在缓慢移位。

To work this around, the modified python file:

要解决这个问题，修改后的python文件：

"""
videoCapture.py
"""
import cv2, sys
import time

if sys.platform == "win32":
    import os, msvcrt
    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)

cap = cv2.VideoCapture(0)                    # 0 is for /dev/video0
while True :
    ret, frm = cap.read()
    sys.stdout.write( frm.tostring() )

To test if piping the raw video is successful, use ffplay. Make sure you specify a higher framerate than what is coming from the pipe, otherwise the video will start to lag

要测试原始视频是否成功，请使用ffplay。确保指定的帧速率高于来自管道的帧速率，否则视频将开始滞后

python videoCapture.py | ffplay -f rawvideo -pix_fmt bgr24 -s 640x480 -framerate 40 -i -

0  

Not sure if this is Mac OS-specific, or python3-specific, but I needed to cast the frame to a string in order for this to work for me, like so:

不确定这是Mac OS特定的，还是特定于python3的，但我需要将框架转换为字符串才能使其适用于我，如下所示：

sys.stdout.write(str(frame.tostring()))