it only fixes stuff on that randomvoting

Yes. You really need to do it on a case-by-case basis, as the fix for each problem site can be different.

However, you can specify multiple match_patterns in permissions in the manifest file and in the urls array in the listener background.js to make the specific fix apply to more URLs.

You could set "<all_urls>" in the manifest file and add multiple listeners (one for each site) in background.js where you can then do specific fixes per site.

What is the difference between .js and .json extensions?

.json is for specifying Javascript data objects. .js is for directly executable Javascript code. In this case, think of JSON like an ini file or a prefs file etc.

@joshl said in Cannot access (download?) to view .mp4 video files.:

Do you use the Notepad

Yes. Notepad or any text editor is fine. Notepad++ is what I use in this case.

In it, put these files:

manifest.json:

{
    "background": {
        "scripts": ["background.js"]
    },
    "incognito" : "spanning",
    "description": "Fix MP4 Type on randomvoting.com", 
    "browser_action": {
        
    },
    "manifest_version": 2, 
    "name": "Fix MP4 Type on randomvoting.com", 
    "permissions": [
        "webRequest", 
        "webRequestBlocking", 
        "http://www.randomvoting.com/videos/*.mp4"
    ],
    "version": "0.1"
}

background.js:

chrome.webRequest.onHeadersReceived.addListener(function(details) {
    var headers = details.responseHeaders;
    for (var i = 0; i < headers.length; ++i) {
        if (headers[i].name === "Content-Type") {
            headers[i].value = "video/mp4"
            break;
        }
    }
    return {responseHeaders: headers};
}, {urls: ['http://www.randomvoting.com/videos/*.mp4']}, ['responseHeaders', 'blocking']);

Then, goto opera://extensions, switch to developer mode, click "load unpacked extension" and point it to the folder.

Also, adjust opera://flags/#autoplay-policy how you want.

Then, when navigating to http://www.randomvoting.com/videos/capstick_came_home.mp4, it should play inside Opera once enough of it is buffered. You can then use the download option on the video toolbar to download it if you want.

Anyway, play with and tweak the extension to your liking.

You'll then see a request/repsponse connection being logged. Left-click it and click the "Headers" tab. What you will see is:

Content-Type: text/plain

That's the reason for the problem as suggested previously.

Now, browsers could try to sniff the content, figure out that it's actually an mp4 and play it etc. But, the site also sends:

X-Content-Type-Options: nosniff

that tells the browser not to do that and to treat it as text/plain just like the site says.

An extension that allows you to modify the content-type in response headers for files with mp4 extensions in the http://www.randomvoting.com/videos/ directory to video/mp4 (with perhaps removing the no-sniff header too) might help if you can't get the site to fix it.

It means that the problem is probably on the page itself, maybe the wrong mime type is being sent to Opera.

So what one would do with that?
I also have that trouble with mime type with some hosts sometimes. Not usually recently, but still. When it happens, the download extension does catch the file to download.

BTW, the same problem happens on Edge and Firefox tries to download the file instead of trying to play it.

link text

Eric alias Randomist

(And I have not seen such a comprehensive collection of Emoji. Quite incredible!)

These two screenshots seem to illustrate what I'm seeing:

link text

And version information and OS:

link text

The link to the file is:

link text

In the past I've used 'MSI Web Video' to produce shockwave flash (.swf) files that rendered okay in Opera. See, for example:

link text

Eric Carwardine alias Randomist

Right click on the link, save the file and try to open it in Opera to see if it plays.

What's your version of Opera, OS and link to the file?