public async Task Start()
{
var streams = M3UPlaylist.Parse(await _client.GetStringAsync(_slideUrl));
// This will typically select a 720p stream with 3500 Kbps bitrate, the best on offer
var bestStream = streams.StreamItems.OrderByDescending(s => s.Width * s.Height).First();
var url = _slideUrl.Substring(0, _slideUrl.LastIndexOf('/') + 1);
var itemsListSrc = await _client.GetStringAsync(url + bestStream.Path);
var itemsList = M3UPlaylist.Parse(itemsListSrc);
_client.DefaultRequestHeaders.Remove("accept");
_client.DefaultRequestHeaders.Add("accept", "*/*");
// Prefetch all the AES keys
foreach (var key in itemsList.Keys)
{
key.Key = await _client.GetByteArrayAsync(key.Uri);
if (key.Key == null || key.Key.Length != 16)
{
throw new Exception("Failed to retrieve AES key: " + key.Uri);
}
}
var videoBaseUrl = url + bestStream.Path;
videoBaseUrl = videoBaseUrl.Substring(0, videoBaseUrl.LastIndexOf('/') + 1);
int i = 0;
foreach (var video in itemsList.VideoItems)
{
var videoUrl = videoBaseUrl + video.Path;
var raw = await _client.GetByteArrayAsync(videoUrl);
i++;
Aes crypto = Aes.Create();
var decryptor = crypto.CreateDecryptor(video.Key.Key, video.Key.IV);
byte[] decrypted = decryptor.TransformFinalBlock(raw, 0, raw.Length);
if (NewVideoSequence != null)
{
NewVideoSequence(this, new VideoSequenceData {
SourceUrl = videoUrl,
RawData = decrypted,
SequenceNumber = video.Sequence,
PartsInQueue = itemsList.VideoItems.Count - i
});
}
}
}
public static M3UPlaylist Parse(string content)
{
var lines = content.Split(new[] { "\r\n", "\n" }, StringSplitOptions.RemoveEmptyEntries);
if (lines[0] != "#EXTM3U")
{
return(null);
}
var ret = new M3UPlaylist();
int seq = 0;
M3UEncryptionKey currentKey = null;
for (int i = 1; i < lines.Length; i++)
{
var line = lines[i];
if (line.StartsWith("#EXT-X-STREAM-INF:") && (i + 1) != lines.Length)
{
var props = ParseProperties(line);
var item = new M3UStreamItem {
Path = lines[++i]
};
if (props.ContainsKey("RESOLUTION"))
{
var rect = props["RESOLUTION"].Split('x');
item.Width = int.Parse(rect[0]);
item.Height = int.Parse(rect[1]);
}
if (props.ContainsKey("BANDWIDTH"))
{
item.Bandwidth = int.Parse(props["BANDWIDTH"]);
}
if (props.ContainsKey("AVERAGE-BANDWIDTH"))
{
item.AverageBandwidth = int.Parse(props["AVERAGE-BANDWIDTH"]);
}
ret.StreamItems.Add(item);
}
else if (line.StartsWith("#EXT-X-MEDIA-SEQUENCE"))
{
ret.MediaSequence = int.Parse(line.Split(':')[1]);
}
else if (line.StartsWith("#EXT-X-KEY"))
{
var props = ParseProperties(line);
currentKey = new M3UEncryptionKey
{
Method = props["METHOD"],
Uri = props["URI"],
};
var iv = props["IV"];
iv = iv.Substring(2);
currentKey.IV = new byte[iv.Length / 2];
for (int j = 0; j < (iv.Length / 2); j++)
{
currentKey.IV[j] = byte.Parse(iv[j * 2 + 0].ToString() + iv[j * 2 + 1], NumberStyles.HexNumber);
}
ret.Keys.Add(currentKey);
}
else if (line.StartsWith("#EXTINF") && (i + 1) != lines.Length)
{
ret.VideoItems.Add(new M3UVideoItem {
Path = lines[++i],
Sequence = ret.MediaSequence + (seq++),
Key = currentKey
});
}
}
return(ret);
}
