Exemple #1
0
        public unsafe AudioMetadata ReadMetadata(Stream stream)
        {
            OggStream?oggStream = null;

#if NETSTANDARD2_0
            var buffer = ArrayPool <byte> .Shared.Rent(4096);
#else
            Span <byte> buffer = stackalloc byte[4096];
#endif

            try
            {
                using (var sync = new OggSync())
                {
                    OggPage page;

                    do
                    {
                        // Read from the buffer into a page
                        while (!sync.PageOut(out page))
                        {
#if NETSTANDARD2_0
                            var bytesRead = stream.Read(buffer, 0, buffer.Length);
#else
                            var bytesRead = stream.Read(buffer);
#endif
                            if (bytesRead == 0)
                            {
                                throw new AudioInvalidException("No Ogg stream was found.");
                            }

                            var nativeBuffer = new Span <byte>(sync.Buffer(bytesRead).ToPointer(), bytesRead);
#if NETSTANDARD2_0
                            buffer.AsSpan().Slice(0, bytesRead).CopyTo(nativeBuffer);
#else
                            buffer.Slice(0, bytesRead).CopyTo(nativeBuffer);
#endif
                            sync.Wrote(bytesRead);
                        }

                        oggStream ??= new(SafeNativeMethods.OggPageSerialNo(page));
                        oggStream.PageIn(page);

                        while (oggStream.PacketOut(out var packet))
                        {
                            if (packet.PacketNumber == 1)
                            {
                                return(new CommentHeaderToMetadataAdapter(packet));
                            }
                        }
                    } while (!SafeNativeMethods.OggPageEos(page));

                    throw new AudioInvalidException("The end of the Ogg stream was reached without finding a header.");
                }
            }
            finally
            {
#if NETSTANDARD2_0
                ArrayPool <byte> .Shared.Return(buffer);
#endif
                oggStream?.Dispose();
            }
        }
Exemple #2
0
        public unsafe void WriteMetadata(Stream stream, AudioMetadata metadata, SettingDictionary settings)
        {
            using (var tempStream = new TempFileStream())
            {
                OggStream inputOggStream  = null;
                OggStream outputOggStream = null;
#if NETSTANDARD2_0
                var buffer = ArrayPool <byte> .Shared.Rent(4096);
#else
                Span <byte> buffer = stackalloc byte[4096];
#endif

                try
                {
                    using (var sync = new OggSync())
                    {
                        var     headerWritten = false;
                        OggPage page;
                        var     pagesWritten = 0u;

                        do
                        {
                            // Read from the buffer into a page
                            while (!sync.PageOut(out page))
                            {
#if NETSTANDARD2_0
                                var bytesRead = stream.Read(buffer, 0, buffer.Length);
#else
                                var bytesRead = stream.Read(buffer);
#endif
                                if (bytesRead == 0)
                                {
                                    throw new AudioInvalidException("No Ogg stream was found.");
                                }

                                var nativeBuffer = new Span <byte>(sync.Buffer(bytesRead).ToPointer(), bytesRead);
#if NETSTANDARD2_0
                                buffer.AsSpan().Slice(0, bytesRead).CopyTo(nativeBuffer);
#else
                                buffer.Slice(0, bytesRead).CopyTo(nativeBuffer);
#endif
                                sync.Wrote(bytesRead);
                            }

                            if (inputOggStream == null)
                            {
                                inputOggStream = new OggStream(SafeNativeMethods.OggPageSerialNo(page));
                            }
                            if (outputOggStream == null)
                            {
                                outputOggStream = new OggStream(inputOggStream.SerialNumber);
                            }

                            // Write new header page(s) using a modified comment packet
                            if (!headerWritten)
                            {
                                inputOggStream.PageIn(page);

                                while (inputOggStream.PacketOut(out var packet))
                                {
                                    switch (packet.PacketNumber)
                                    {
                                    case 0:
                                        outputOggStream.PacketIn(packet);
                                        break;

                                    // Substitute the new comment packet
                                    case 1:
                                        using (var adapter = new MetadataToOpusCommentAdapter(metadata))
                                        {
                                            adapter.HeaderOut(out var commentPacket);
                                            outputOggStream.PacketIn(commentPacket);
                                        }

                                        headerWritten = true;
                                        break;

                                    default:
                                        throw new AudioInvalidException("Missing header packet.");
                                    }
                                }

                                // Flush at the end of each header
                                while (outputOggStream.Flush(out var outPage))
                                {
                                    WritePage(outPage, tempStream);
                                    pagesWritten++;
                                }
                            }
                            else
                            {
                                // Copy the existing data pages verbatim, with updated sequence numbers
                                UpdateSequenceNumber(ref page, pagesWritten);
                                WritePage(page, tempStream);
                                pagesWritten++;
                            }
                        } while (!SafeNativeMethods.OggPageEos(page));

                        // Once the end of the input is reached, overwrite the original file and return
                        stream.Position = 0;
                        stream.SetLength(tempStream.Length);
                        tempStream.Position = 0;
                        tempStream.CopyTo(stream);
                    }
                }
                finally
                {
#if NETSTANDARD2_0
                    ArrayPool <byte> .Shared.Return(buffer);
#endif
                    inputOggStream?.Dispose();
                    outputOggStream?.Dispose();
                }
            }
        }