Streaming MP4 video through .NET HTML5

眉间皱痕 提交于 2019-12-03 08:00:57

FIXED!

The problem here is presumably something to do with the HTML5 video implementation of range-requests. Without supporting range-requests in the page being used to SERVE the video, they just won't work.

It was this very helpful post from Scott Mitchell which set me on the case: http://dotnetslackers.com/articles/aspnet/Range-Specific-Requests-in-ASP-NET.aspx

And another helpful post from Chris Coulson which provided the implementation in C# for the solution! http://blogs.visigo.com/chriscoulson/easy-handling-of-http-range-requests-in-asp-net/

My vb.net port of the code Chris found is below, to implement it simply put this in your page:

system.web.httpcontext.current.Response.ContentType = "video/" & convertFormat.toString
RangeDownload(convertedVideo, system.web.httpcontext.current)

VB.NET CODE:

private sub RangeDownload( fullpath as string, context as HttpContext)

    dim size as long
    dim start as long
    dim theend as long
    dim length as long
    dim fp as long =0
    using reader as new StreamReader(fullpath)
        size = reader.BaseStream.Length
        start = 0
        theend = size - 1
        length = size
        '/ Now that we've gotten so far without errors we send the accept range header
        '* At the moment we only support single ranges.
        '* Multiple ranges requires some more work to ensure it works correctly
        '* and comply with the spesifications: http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
        '*
        '* Multirange support annouces itself with:
        '* header('Accept-Ranges: bytes');
        '*
        '* Multirange content must be sent with multipart/byteranges mediatype,
        '* (mediatype = mimetype)
        '* as well as a boundry header to indicate the various chunks of data.
        '*/
        context.Response.AddHeader("Accept-Ranges", "0-" + size)
        '// header('Accept-Ranges: bytes')
        '// multipart/byteranges
        '// http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2

        if (not String.IsNullOrEmpty(context.Request.ServerVariables("HTTP_RANGE"))) then
            dim anotherStart as long = start
            dim anotherEnd as long = theend
            dim arr_split as string() = context.Request.ServerVariables("HTTP_RANGE").Split("=") 'new char[] { Convert.ToChar("=") })
            dim range as string = arr_split(1)

            '// Make sure the client hasn't sent us a multibyte range
            if (range.IndexOf(",") > -1) then
                '// (?) Shoud this be issued here, or should the first
                '// range be used? Or should the header be ignored and
                '// we output the whole content?
                context.Response.AddHeader("Content-Range", "bytes " & start & "-" & theend & "/" & size)
                throw new HttpException(416, "Requested Range Not Satisfiable")
            end if

            '// If the range starts with an '-' we start from the beginning
            '// If not, we forward the file pointer
            '// And make sure to get the end byte if spesified
            if (range.StartsWith("-")) then
                '// The n-number of the last bytes is requested
                anotherStart = size - Convert.ToInt64(range.Substring(1))
            else
                arr_split = range.Split("-")
                anotherStart = Convert.ToInt64(arr_split(0))
                dim temp as long = 0
                if (arr_split.Length > 1 andalso Int64.TryParse(arr_split(1).ToString(), temp)) then
                    anotherEnd =  Convert.ToInt64(arr_split(1))
                else
                    anotherEnd = size
                end if
            end if
            '/* Check the range and make sure it's treated according to the specs.
            ' * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
            ' */
            '// End bytes can not be larger than $end.
            if (anotherEnd > theend) then
                anotherEnd = theend
            else
                anotherEnd = anotherEnd
            end if
            '// Validate the requested range and return an error if it's not correct.
            if (anotherStart > anotherEnd or anotherStart > size - 1 or anotherEnd >= size) then
                context.Response.AddHeader("Content-Range", "bytes " + start + "-" + theend + "/" + size)
                throw new HttpException(416, "Requested Range Not Satisfiable")
            end if

            start = anotherStart
            theend = anotherEnd

            length = theend - start + 1 '// Calculate new content length
            fp = reader.BaseStream.Seek(start, SeekOrigin.Begin)
            context.Response.StatusCode = 206
        end if
    end using

    '// Notify the client the byte range we'll be outputting
    context.Response.AddHeader("Content-Range", "bytes " & start & "-" & theend & "/" & size)
    context.Response.AddHeader("Content-Length", length.ToString())
    '// Start buffered download
    context.Response.WriteFile(fullpath, fp, length)
    context.Response.End()
end sub
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