Libation/AaxDecrypter/AaxcDownloadConverter.cs
2021-06-28 15:35:43 -06:00

280 lines
10 KiB
C#

using Dinah.Core;
using Dinah.Core.Diagnostics;
using Dinah.Core.IO;
using Dinah.Core.StepRunner;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
namespace AaxDecrypter
{
public interface ISimpleAaxToM4bConverter
{
event EventHandler<int> DecryptProgressUpdate;
bool Run();
string AppName { get; set; }
string outDir { get; }
string outputFileName { get; }
ChapterInfo chapters { get; }
void SetOutputFilename(string outFileName);
string Title { get; }
string Author { get; }
string Narrator { get; }
byte[] CoverArt { get; }
}
public interface IAdvancedAaxcToM4bConverter : ISimpleAaxToM4bConverter
{
void Cancel();
bool Step1_CreateDir();
bool Step2_DownloadAndCombine();
bool Step3_RestoreMetadata();
bool Step4_CreateCue();
bool Step5_CreateNfo();
}
public class AaxcDownloadConverter : IAdvancedAaxcToM4bConverter
{
public event EventHandler<int> DecryptProgressUpdate;
public event EventHandler<TimeSpan> DecryptTimeRemaining;
public string AppName { get; set; } = nameof(AaxcDownloadConverter);
public string outDir { get; private set; }
public string outputFileName { get; private set; }
public ChapterInfo chapters { get; private set; }
public string Title => aaxcTagLib.Tag.Title.Replace(" (Unabridged)", "");
public string Author => aaxcTagLib.Tag.FirstPerformer ?? "[unknown]";
public string Narrator => aaxcTagLib.GetTag(TagLib.TagTypes.Apple).Narrator;
public byte[] CoverArt => aaxcTagLib.Tag.Pictures.Length > 0 ? aaxcTagLib.Tag.Pictures[0].Data.Data : default;
private TagLib.Mpeg4.File aaxcTagLib { get; set; }
private StepSequence steps { get; }
private DownloadLicense downloadLicense { get; set; }
private FFMpegAaxcProcesser aaxcProcesser;
public static async Task<AaxcDownloadConverter> CreateAsync(string outDirectory, DownloadLicense dlLic, ChapterInfo chapters = null)
{
var converter = new AaxcDownloadConverter(outDirectory, dlLic, chapters);
await converter.prelimProcessing();
return converter;
}
private AaxcDownloadConverter(string outDirectory, DownloadLicense dlLic, ChapterInfo chapters)
{
ArgumentValidator.EnsureNotNullOrWhiteSpace(outDirectory, nameof(outDirectory));
ArgumentValidator.EnsureNotNull(dlLic, nameof(dlLic));
if (!Directory.Exists(outDirectory))
throw new ArgumentNullException(nameof(outDirectory), "Directory does not exist");
outDir = outDirectory;
steps = new StepSequence
{
Name = "Convert Aax To M4b",
["Step 1: Create Dir"] = Step1_CreateDir,
["Step 2: Download and Combine Audiobook"] = Step2_DownloadAndCombine,
["Step 3: Restore Aaxc Metadata"] = Step3_RestoreMetadata,
["Step 4: Create Cue"] = Step4_CreateCue,
["Step 5: Create Nfo"] = Step5_CreateNfo,
};
downloadLicense = dlLic;
this.chapters = chapters;
}
private async Task prelimProcessing()
{
//Get metadata from the file over http
var client = new System.Net.Http.HttpClient();
client.DefaultRequestHeaders.Add("User-Agent", downloadLicense.UserAgent);
var networkFile = await NetworkFileAbstraction.CreateAsync(client, new Uri(downloadLicense.DownloadUrl));
aaxcTagLib = await Task.Run(() => TagLib.File.Create(networkFile, "audio/mp4", TagLib.ReadStyle.Average) as TagLib.Mpeg4.File);
var defaultFilename = Path.Combine(
outDir,
PathLib.ToPathSafeString(aaxcTagLib.Tag.FirstPerformer??"[unknown]"),
PathLib.ToPathSafeString(aaxcTagLib.Tag.Title.Replace(" (Unabridged)", "")) + ".m4b"
);
SetOutputFilename(defaultFilename);
}
public void SetOutputFilename(string outFileName)
{
outputFileName = PathLib.ReplaceExtension(outFileName, ".m4b");
outDir = Path.GetDirectoryName(outputFileName);
if (File.Exists(outputFileName))
File.Delete(outputFileName);
}
public bool Run()
{
var (IsSuccess, Elapsed) = steps.Run();
if (!IsSuccess)
{
Console.WriteLine("WARNING-Conversion failed");
return false;
}
var speedup = (int)(aaxcTagLib.Properties.Duration.TotalSeconds / (long)Elapsed.TotalSeconds);
Console.WriteLine("Speedup is " + speedup + "x realtime.");
Console.WriteLine("Done");
return true;
}
public bool Step1_CreateDir()
{
ProcessRunner.WorkingDir = outDir;
Directory.CreateDirectory(outDir);
return true;
}
public bool Step2_DownloadAndCombine()
{
aaxcProcesser = new FFMpegAaxcProcesser(downloadLicense);
aaxcProcesser.ProgressUpdate += AaxcProcesser_ProgressUpdate;
bool userSuppliedChapters = chapters != null;
string metadataPath = null;
if (userSuppliedChapters)
{
//Only write chaopters to the metadata file. All other aaxc metadata will be
//wiped out but is restored in Step 3.
metadataPath = Path.Combine(outDir, Path.GetFileName(outputFileName) + ".ffmeta");
File.WriteAllText(metadataPath, chapters.ToFFMeta(true));
}
aaxcProcesser.ProcessBook(
outputFileName,
metadataPath)
.GetAwaiter()
.GetResult();
if (!userSuppliedChapters && aaxcProcesser.Succeeded)
chapters = new ChapterInfo(outputFileName);
if (userSuppliedChapters)
FileExt.SafeDelete(metadataPath);
DecryptProgressUpdate?.Invoke(this, 0);
return aaxcProcesser.Succeeded;
}
private void AaxcProcesser_ProgressUpdate(object sender, TimeSpan e)
{
double averageRate = getAverageProcessRate(e);
double remainingSecsToProcess = (aaxcTagLib.Properties.Duration - e).TotalSeconds;
double estTimeRemaining = remainingSecsToProcess / averageRate;
if (double.IsNormal(estTimeRemaining))
DecryptTimeRemaining?.Invoke(this, TimeSpan.FromSeconds(estTimeRemaining));
double progressPercent = 100 * e.TotalSeconds / aaxcTagLib.Properties.Duration.TotalSeconds;
DecryptProgressUpdate?.Invoke(this, (int)progressPercent);
}
/// <summary>
/// Calculates the average processing rate based on the last 2 to <see cref="MAX_NUM_AVERAGE"/> samples.
/// </summary>
/// <param name="lastProcessedPosition">Position in the audio file last processed</param>
/// <returns>The average processing rate, in book_duration_seconds / second.</returns>
private double getAverageProcessRate(TimeSpan lastProcessedPosition)
{
streamPositions.Enqueue(new StreamPosition
{
ProcessPosition = lastProcessedPosition,
EventTime = DateTime.Now,
});
if (streamPositions.Count < 2)
return double.PositiveInfinity;
//Calculate the harmonic mean of the last 2 to MAX_NUM_AVERAGE progress updates
//Units are Book_Duration_Seconds / second
var lastPos = streamPositions.Count > MAX_NUM_AVERAGE ? streamPositions.Dequeue() : null;
double harmonicDenominator = 0;
int harmonicNumerator = 0;
foreach (var pos in streamPositions)
{
if (lastPos is null)
{
lastPos = pos;
continue;
}
double dP = (pos.ProcessPosition - lastPos.ProcessPosition).TotalSeconds;
double dT = (pos.EventTime - lastPos.EventTime).TotalSeconds;
harmonicDenominator += dT / dP;
harmonicNumerator++;
lastPos = pos;
}
double harmonicMean = harmonicNumerator / harmonicDenominator;
return harmonicMean;
}
private const int MAX_NUM_AVERAGE = 15;
private class StreamPosition
{
public TimeSpan ProcessPosition { get; set; }
public DateTime EventTime { get; set; }
}
private Queue<StreamPosition> streamPositions = new Queue<StreamPosition>();
/// <summary>
/// Copy all aacx metadata to m4b file, including cover art.
/// </summary>
public bool Step3_RestoreMetadata()
{
var outFile = new TagLib.Mpeg4.File(outputFileName, TagLib.ReadStyle.Average);
var destTags = outFile.GetTag(TagLib.TagTypes.Apple) as TagLib.Mpeg4.AppleTag;
destTags.Clear();
var sourceTag = aaxcTagLib.GetTag(TagLib.TagTypes.Apple) as TagLib.Mpeg4.AppleTag;
//copy all metadata fields in the source file, even those that TagLib doesn't
//recognize, to the output file.
//NOTE: Chapters aren't stored in MPEG-4 metadata. They are encoded as a Timed
//Text Stream (MPEG-4 Part 17), so taglib doesn't read or write them.
foreach (var stag in sourceTag)
{
destTags.SetData(stag.BoxType, stag.Children.Cast<TagLib.Mpeg4.AppleDataBox>().ToArray());
}
outFile.Save();
return true;
}
public bool Step4_CreateCue()
{
File.WriteAllText(PathLib.ReplaceExtension(outputFileName, ".cue"), Cue.CreateContents(Path.GetFileName(outputFileName), chapters));
return true;
}
public bool Step5_CreateNfo()
{
File.WriteAllText(PathLib.ReplaceExtension(outputFileName, ".nfo"), NFO.CreateContents(AppName, aaxcTagLib, chapters));
return true;
}
public void Cancel()
{
aaxcProcesser.Cancel();
}
}
}