如何正确地将模拟网络摄像头视频提供给Chrome? [英] How can I correctly provide a mock webcam video to Chrome?

问题描述

我正在尝试针对需要网络摄像头供稿运行的产品在Chrome中运行端到端测试.据我了解，这意味着使用--use-file-for-fake-video-capture="/path/to/video.y4m"命令行参数将虚假的网络摄像头视频提供给Chrome.然后它将使用它作为网络摄像头视频.

I'm trying to run end-to-end testing in Chrome for a product that requires a webcam feed halfway through to operate. From what I understand this means providing a fake webcam video to Chrome using the --use-file-for-fake-video-capture="/path/to/video.y4m" command line argument. It will then use that as a webcam video.

但是，无论我提供了什么y4m文件，在这些条件下运行的Chrome都会出现以下错误:

However, no matter what y4m file I provide, I get the following error from Chrome running under these conditions:

DOMException: Could not start video source
{
  code: 0,
  message: "Could not start video source",
  name: "NotReadableError"
}

我可以很好地使用--use-file-for-fake-audio-capture提供音频文件，Chrome可以很好地工作.视频一直是我的重点.

Notably I can provide an audio file just fine using --use-file-for-fake-audio-capture and Chrome will work with it well. The video has been my sticking point.

此错误来自以下简单的mediaDevices请求:

This error comes out of the following straightforward mediaDevices request:

navigator.mediaDevices.getUserMedia({ video: true, audio: true })
  .then(data => {
    // do stuff
  })
  .catch(err => {
    // oh no!
  });

(提供视频文件时，它总是打"oh no！"分支.)

(This always hits the "oh no!" branch when a video file is provided.)

我一直在使用以下命令行参数运行Chrome(添加了换行符以提高可读性)，并且我使用的是Mac，因此使用open命令:

I've been running Chrome with the following command line arguments (newlines added for readability), and I'm using a Mac hence the open command:

open -a "Google Chrome" --args
  --disable-gpu
  --use-fake-device-for-media-stream
  --use-file-for-fake-video-capture="~/Documents/mock/webcam.y4m"
  --use-file-for-fake-audio-capture="~/Documents/mock/microphone.wav"

webcam.y4m和microphone.wav是从我录制的视频文件生成的.

webcam.y4m and microphone.wav were generated from a video file I recorded.

我首先使用浏览器的MediaRecorder录制了20秒的mp4视频，下载了结果，然后使用以下命令行命令进行了转换:

I first recorded a twenty-second mp4 video using my browser's MediaRecorder, downloaded the result, and converted it using the following command line commands:

ffmpeg -y -i original.mp4 -f wav -vn microphone.wav
ffmpeg -y -i original.mp4 webcam.y4m

如果这行不通，我使用在Quicktime中录制的二十秒电影文件尝试了相同的操作:

When this didn't work, I tried the same using a twenty-second movie file I recorded in Quicktime:

ffmpeg -y -i original.mov -f wav -vn microphone.wav
ffmpeg -y -i original.mov webcam.y4m

当同样失败时，我直接去 the它提供了示例y4m文件列表，并下载了祖母文件，并提供了该文件作为Chrome的命令行参数:

When that also failed, I went straight to the Chromium file that explains fake video capture, went to the example y4m file list it provided, and downloaded the grandma file and provided that as a command line argument to Chrome instead:

open -a "Google Chrome" --args
  --disable-gpu
  --use-fake-device-for-media-stream
  --use-file-for-fake-video-capture="~/Documents/mock/grandma_qcif.y4m"
  --use-file-for-fake-audio-capture="~/Documents/mock/microphone.wav"

在这些情况下，Chrome为我提供了 exact 相同的错误.

Chrome provides me with the exact same error in all of these situations.

Chrome唯一不会因该mediaDevices请求而出错的时间是当我完全忽略该视频时:

The only time Chrome doesn't error out with that mediaDevices request is when I omit the video completely:

open -a "Google Chrome" --args
  --disable-gpu
  --use-fake-device-for-media-stream
  --use-file-for-fake-audio-capture="~/Documents/mock/microphone.wav"

C420mpeg2的会计处理

TestRTC 建议，如果我给它一个C420mpeg2文件，Chrome将会崩溃"，并建议您只需替换元数据即可解决此问题.实际上，我从ffmpeg生成的视频文件为我提供了以下标头:

Accounting for C420mpeg2

TestRTC suggests Chrome will "crash" if I give it a C420mpeg2 file, and recommends that simply replacing the metadata fixes the issue. Indeed the video file I generate from ffmpeg gives me the following header:

YUV4MPEG2 W1280 H720 F30:1 Ip A1:1 C420mpeg2 XYSCSS=420MPEG2

使用此文件运行时，Chrome实际上并没有崩溃，我只是得到了上面的错误.如果按照TestRTC的建议，如果我将视频文件编辑到以下标题，则会遇到相同的情况:

Chrome doesn't actually crash when run with this file, I just get the error above. If I edit the video file to the following header though per TestRTC's recommendations I get the same situation:

YUV4MPEG2 W1280 H720 F30:1 Ip A1:1 C420 XYSCSS=420MPEG2

在这些情况下，视频文件仍然给我上述错误.

The video file still gives me the above error in these conditions.

如何为该命令行参数向Chrome提供视频文件?

How should I be providing a video file to Chrome for this command line argument?

我应该如何录制或创建视频文件?

How should I be recording or creating the video file?

我应该如何将其转换为y4m?

How should I convert it to y4m?

推荐答案

阅读了您提供的链接后，我注意到我们也可以提供 mjpeg .

After reading the link you provided I noticed that we can also provide an mjpeg.

取决于您的测试要求-这可能对您就足够了.

Depending on what your test requirements - this may be sufficient for you.

ffmpeg -i oldfile.mp4 newfile.mjpeg

然后我使用以下方法进行了测试:

then I tested using:

google-chrome --use-fake-device-for-media-stream --use-file-for-fake-video-capture=newfile.mjpeg

导航到跟踪JS 后，我可以看到正在播放的视频.

After navigating to Tracking JS I could see the video being played back.

我希望对您有用！

这篇关于如何正确地将模拟网络摄像头视频提供给Chrome?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！