| | | 1 | | using System; |
| | | 2 | | using System.Collections.Generic; |
| | | 3 | | using System.IO; |
| | | 4 | | using Jellyfin.MediaEncoding.Keyframes.Matroska.Extensions; |
| | | 5 | | using Jellyfin.MediaEncoding.Keyframes.Matroska.Models; |
| | | 6 | | using NEbml.Core; |
| | | 7 | | |
| | | 8 | | namespace Jellyfin.MediaEncoding.Keyframes.Matroska; |
| | | 9 | | |
| | | 10 | | /// <summary> |
| | | 11 | | /// The keyframe extractor for the matroska container. |
| | | 12 | | /// </summary> |
| | | 13 | | public static class MatroskaKeyframeExtractor |
| | | 14 | | { |
| | | 15 | | /// <summary> |
| | | 16 | | /// Extracts the keyframes in ticks (scaled using the container timestamp scale) from the matroska container. |
| | | 17 | | /// </summary> |
| | | 18 | | /// <param name="filePath">The file path.</param> |
| | | 19 | | /// <returns>An instance of <see cref="KeyframeData"/>.</returns> |
| | | 20 | | public static KeyframeData GetKeyframeData(string filePath) |
| | 0 | 21 | | { |
| | 0 | 22 | | using var stream = File.OpenRead(filePath); |
| | 0 | 23 | | using var reader = new EbmlReader(stream); |
| | | 24 | | |
| | 0 | 25 | | var seekHead = reader.ReadSeekHead(); |
| | | 26 | | // External lib does not support seeking backwards (yet) |
| | | 27 | | Info info; |
| | | 28 | | ulong videoTrackNumber; |
| | 0 | 29 | | if (seekHead.InfoPosition < seekHead.TracksPosition) |
| | 0 | 30 | | { |
| | 0 | 31 | | info = reader.ReadInfo(seekHead.InfoPosition); |
| | 0 | 32 | | videoTrackNumber = reader.FindFirstTrackNumberByType(seekHead.TracksPosition, MatroskaConstants.TrackTypeVid |
| | 0 | 33 | | } |
| | | 34 | | else |
| | 0 | 35 | | { |
| | 0 | 36 | | videoTrackNumber = reader.FindFirstTrackNumberByType(seekHead.TracksPosition, MatroskaConstants.TrackTypeVid |
| | 0 | 37 | | info = reader.ReadInfo(seekHead.InfoPosition); |
| | 0 | 38 | | } |
| | | 39 | | |
| | 0 | 40 | | var keyframes = new List<long>(); |
| | 0 | 41 | | reader.ReadAt(seekHead.CuesPosition); |
| | 0 | 42 | | reader.EnterContainer(); |
| | | 43 | | |
| | 0 | 44 | | while (reader.FindElement(MatroskaConstants.CuePoint)) |
| | 0 | 45 | | { |
| | 0 | 46 | | reader.EnterContainer(); |
| | 0 | 47 | | ulong? trackNumber = null; |
| | | 48 | | // Mandatory element |
| | 0 | 49 | | reader.FindElement(MatroskaConstants.CueTime); |
| | 0 | 50 | | var cueTime = reader.ReadUInt(); |
| | | 51 | | |
| | | 52 | | // Mandatory element |
| | 0 | 53 | | reader.FindElement(MatroskaConstants.CueTrackPositions); |
| | 0 | 54 | | reader.EnterContainer(); |
| | 0 | 55 | | if (reader.FindElement(MatroskaConstants.CuePointTrackNumber)) |
| | 0 | 56 | | { |
| | 0 | 57 | | trackNumber = reader.ReadUInt(); |
| | 0 | 58 | | } |
| | | 59 | | |
| | 0 | 60 | | reader.LeaveContainer(); |
| | | 61 | | |
| | 0 | 62 | | if (trackNumber == videoTrackNumber) |
| | 0 | 63 | | { |
| | 0 | 64 | | keyframes.Add(ScaleToTicks(cueTime, info.TimestampScale)); |
| | 0 | 65 | | } |
| | | 66 | | |
| | 0 | 67 | | reader.LeaveContainer(); |
| | 0 | 68 | | } |
| | | 69 | | |
| | 0 | 70 | | reader.LeaveContainer(); |
| | | 71 | | |
| | 0 | 72 | | var result = new KeyframeData(ScaleToTicks(info.Duration ?? 0, info.TimestampScale), keyframes); |
| | 0 | 73 | | return result; |
| | 0 | 74 | | } |
| | | 75 | | |
| | | 76 | | private static long ScaleToTicks(ulong unscaledValue, long timestampScale) |
| | 0 | 77 | | { |
| | | 78 | | // TimestampScale is in nanoseconds, scale it to get the value in ticks, 1 tick == 100 ns |
| | 0 | 79 | | return (long)unscaledValue * timestampScale / 100; |
| | 0 | 80 | | } |
| | | 81 | | |
| | | 82 | | private static long ScaleToTicks(double unscaledValue, long timestampScale) |
| | 0 | 83 | | { |
| | | 84 | | // TimestampScale is in nanoseconds, scale it to get the value in ticks, 1 tick == 100 ns |
| | 0 | 85 | | return Convert.ToInt64(unscaledValue * timestampScale / 100); |
| | 0 | 86 | | } |
| | | 87 | | } |