public static async Task <ParseResult <Mp3File> > ParseMetadataAsync(IBinaryStream stream)
{
var streamLength = await stream.GetLengthAsync().ConfigureAwait(false);
stream.Position = 0;
var id3v2 = (Id3v2)null;
if (await Id3v2.IsPointingToHeaderAsync(stream).ConfigureAwait(false))
{
id3v2 = await Id3v2.ParseAsync(stream).ConfigureAwait(false);
return(ParseResult <Mp3File> .Create(new Mp3File()
{
Metadata = new Mp3Metadata(id3v2)
}));
}
else
{
return(ParseResult <Mp3File> .Create(new Mp3File()
{
Metadata = new Mp3Metadata(null)
}));
}
}
public static async Task SkipAsync(IBinaryStream stream)
{
stream.Position += 3;
var majorVersion = await stream.ReadByteAsync().ConfigureAwait(false);
var revision = await stream.ReadByteAsync().ConfigureAwait(false);
var flags = await stream.ReadByteAsync().ConfigureAwait(false);
var size = Id3v2.DecodeSize(await stream.ReadUInt32Async(ByteOrder.BigEndian).ConfigureAwait(false));
var newStreamPosition = stream.Position + size;
if (await stream.GetLengthAsync().ConfigureAwait(false) < newStreamPosition)
{
newStreamPosition = await stream.GetLengthAsync().ConfigureAwait(false);
}
stream.Position = newStreamPosition;
}
public static async Task <ParseResult <Mpeg4File> > ParseAsync(IBinaryStream stream, ParseOptions options)
{
try
{
stream.Position = 4;
if (await stream.ReadStringAsync(4) != "ftyp")
{
return(ParseResult <Mpeg4File> .CreateUnknownFormat());
}
var file = new Mpeg4File();
stream.Position = 0;
var streamLength = await stream.GetLengthAsync().ConfigureAwait(false);
while (stream.Position < streamLength)
{
file.Boxes.Add(await Mpeg4File.ReadBoxAsync(stream, await stream.GetLengthAsync().ConfigureAwait(false)));
}
if (options == ParseOptions.Metadata)
{
var mediaData = file.Contains("mdat") ? file["mdat"] : null;
var metadataItems = file.Contains("moov.udta.meta.ilst") ? await MetadataItemsBox.CreateAsync(stream, file["moov.udta.meta.ilst"]).ConfigureAwait(false) : null;
var mediaHeader = file.Contains("moov.trak.mdia.mdhd") ? await MediaHeaderBox.CreateAsync(stream, file["moov.trak.mdia.mdhd"]).ConfigureAwait(false) : null;
file.Metadata = new Mpeg4Metadata(metadataItems?.Cover, mediaHeader?.Duration, mediaHeader?.TimeScale, mediaData?.Length);
}
return(ParseResult <Mpeg4File> .Create(file));
}
catch (Exception exception)
{
return(ParseResult <Mpeg4File> .Create(exception));
}
}
public static async Task <ParseResult <Mp3File> > ParseFullMetadataAsync(IBinaryStream stream)
{
var streamLength = await stream.GetLengthAsync().ConfigureAwait(false);
stream.Position = 0;
var file = new Mp3File();
var id3v2 = await Id3v2.IsPointingToHeaderAsync(stream).ConfigureAwait(false) ? await Id3v2.ParseAsync(stream).ConfigureAwait(false) : null;
var collectSamplesResult = await CollectSamplesAsync(stream, streamLength, 1).ConfigureAwait(false);
if (collectSamplesResult.Item1.Count == 0)
{
file.Metadata = new Mp3Metadata(id3v2);
return(ParseResult <Mp3File> .Create(file));
}
else
{
var firstFrame = collectSamplesResult.Item1[0];
var contentLength = streamLength - stream.Position;
if (collectSamplesResult.Item2 == BitrateType.Constant)
{
var duration = TimeSpan.FromSeconds(Math.Ceiling((contentLength / firstFrame.Length) * firstFrame.Duration.TotalSeconds));
var bitrate = firstFrame.Bitrate;
file.Metadata = new Mp3Metadata(id3v2, bitrate, duration);
}
else
{
var xingFrame = await XingFrame.CreateAsync(stream, firstFrame).ConfigureAwait(false);
if (xingFrame.FramesCount.HasValue)
{
var duration = TimeSpan.FromSeconds(xingFrame.FramesCount.Value * firstFrame.SamplesCount / firstFrame.Frequency);
var averageBitrate = (UInt32)(contentLength / duration.TotalSeconds) * 8;
file.Metadata = new Mp3Metadata(id3v2, averageBitrate, duration);
}
else
{
collectSamplesResult = await CollectSamplesAsync(stream, streamLength, null).ConfigureAwait(false);
file.Metadata = new Mp3Metadata(id3v2, collectSamplesResult.Item4, collectSamplesResult.Item3);
}
}
return(ParseResult <Mp3File> .Create(file));
}
}
public static async Task <ParseResult <Mp3File> > ParseSamplesAsync(IBinaryStream stream)
{
var streamLength = await stream.GetLengthAsync().ConfigureAwait(false);
stream.Position = 0;
if (await Id3v2.IsPointingToHeaderAsync(stream).ConfigureAwait(false))
{
await Id3v2.SkipAsync(stream).ConfigureAwait(false);
}
var collectSamplesResult = await CollectSamplesAsync(stream, streamLength, null).ConfigureAwait(false);
if (collectSamplesResult.Item1.Count == 0)
{
return(ParseResult <Mp3File> .CreateUnknownFormat());
}
var file = new Mp3File();
file.Type = collectSamplesResult.Item2;
file.Samples = collectSamplesResult.Item1;
return(ParseResult <Mp3File> .Create(file));
}
