public bool Init(IStorageFile stream, bool readTags, string stateJson = null)
{
if (stream == null)
{
throw new ArgumentNullException($"Null argument {nameof(stream)} !");
}
_readTags = readTags;
_fileStream = stream;
bsbuf = bsspace_1;
_fileStream.UseReadBuffer(2048);
bool stateIsRestored = false;
if (!string.IsNullOrEmpty(stateJson))
{
var state = JsonConvert.DeserializeObject <Mp3EncoderState>(stateJson);
if (state != null)
{
Args = state.Args;
bsnum = state.bsnum;
firsthead = state.firsthead;
fr = state.frame;
framesize = state.framesize;
fsize = state.fsize;
fsizeold = state.fsizeold;
oldhead = state.oldhead;
ssize = state.ssize;
syncword = state.syncword;
_frameOffsets = (state.Args.FramesFileOffsets?.ToList() ?? null);
// Restore full offset instead of relative offset value.
if (_frameOffsets != null)
{
for (int i = 1; i < _frameOffsets.Count; i++)
{
_frameOffsets[i] += _frameOffsets[i - 1];
}
}
// Seek to the beggining of the current frame.
_fileStream.Seek(state.FileOffset, SeekOrigin.Begin);
// Read current frame data.
//ReadFrame();
stateIsRestored = true;
}
}
if (!stateIsRestored)
{
ReadFrame();
}
return(true);
}
public AudioPackets ReadFrames(int packetsCt)
{
bool isEof = false;
int packets = 0, frameSizeWithHeader = framesize + 4;
var mediaFrames = new List <AudioPacket>();
byte[] frameData = null;
// Calculate read buffer length in order to read all the freames in only one IO-READ call.
if (packetsCt > 1)
{
if ((_frameOffsets?.Count ?? 0) > 0)
{
bool lastPacket = ((int)Args.CurrentPos) + packetsCt >= _frameOffsets.Count;
long lastPacketOffset = lastPacket ? _frameOffsets.Last() + Constants.MAXFRAMESIZE :
_frameOffsets[(int)(Args.CurrentPos + (ulong)packetsCt)];
int readBufferSize = (int)(lastPacketOffset - _frameOffsets[(int)Args.CurrentPos]);
_fileStream.UseReadBuffer(readBufferSize);
}
else
{
_fileStream.UseReadBuffer(frameSizeWithHeader * packetsCt);
}
}
// Read frame in buffer first.
if (framebuffIsEmpty)
{
ReadFrame();
Args.CurrentPos++;
}
// Read current frame packet data.
frameData = new byte[frameSizeWithHeader];
Array.Copy(bsbuf, 512, frameData, 0, frameSizeWithHeader);
mediaFrames.Add(new AudioPacket()
{
Data = frameData,
SamplesPerFrame = Args.IsVBR ? SamplesPerFrame : 0
});
packets++;
while (packets < packetsCt)
{
if (((long)Args.CurrentPos) >= MaxFrames)
{
break;
}
read_again:
int res = ReadFrame(); // Read next frame
if (res == 0 && res != -1)
{
goto read_again;
}
if (res == -2)
{
isEof = true;
break;
}
frameSizeWithHeader = framesize + 4;
// Read current frame packet data.
frameData = new byte[frameSizeWithHeader];
Array.Copy(bsbuf, 512, frameData, 0, frameSizeWithHeader);
mediaFrames.Add(new AudioPacket()
{
Data = frameData,
SamplesPerFrame = Args.IsVBR ? SamplesPerFrame : 0
});
packets++;
Args.CurrentPos++;
}
return(new AudioPackets()
{
IsEof = (isEof || Args.CurrentPos >= (ulong)MaxFrames),
IsVBR = Args.IsVBR,
NumPackets = packets,
SamplesPerFrame = Args.IsVBR ? 0 : SamplesPerFrame,
FramesCt = (ulong)MaxFrames,
Offset = Args.CurrentPos,
Packets = mediaFrames
});
}
