/// <summary>
/// Tries to add an entry created from the frame.
/// </summary>
/// <param name="managedFrame">The managed frame.</param>
/// <returns>
/// True if the index entry was created from the frame.
/// False if the frame is of wrong picture type or if it already existed.
/// </returns>
internal bool TryAdd(VideoFrame managedFrame)
{
// Update the Seek index
if (managedFrame.PictureType != AVPictureType.AV_PICTURE_TYPE_I)
{
return(false);
}
// Create the seek entry
var seekEntry = new VideoSeekIndexEntry(managedFrame);
// Check if the entry already exists.
if (Entries.BinarySearch(seekEntry, LookupComparer) >= 0)
{
return(false);
}
// Add the seek entry and ensure they are sorted.
Entries.Add(seekEntry);
Entries.Sort(LookupComparer);
return(true);
}
/// <summary>
/// Adds the monotonic entries up to a stream duration.
/// </summary>
/// <param name="streamDuration">Duration of the stream.</param>
internal void AddMonotonicEntries(TimeSpan streamDuration)
{
if (Entries.Count < 2)
{
return;
}
while (true)
{
var lastEntry = Entries[Entries.Count - 1];
var prevEntry = Entries[Entries.Count - 2];
var presentationTime = lastEntry.PresentationTime == ffmpeg.AV_NOPTS_VALUE ?
ffmpeg.AV_NOPTS_VALUE :
lastEntry.PresentationTime + (lastEntry.PresentationTime - prevEntry.PresentationTime);
var decodingTime = lastEntry.DecodingTime == ffmpeg.AV_NOPTS_VALUE ?
ffmpeg.AV_NOPTS_VALUE :
lastEntry.DecodingTime + (lastEntry.DecodingTime - prevEntry.DecodingTime);
var startTimeTicks = lastEntry.StartTime.Ticks + (lastEntry.StartTime.Ticks - prevEntry.StartTime.Ticks);
var entry = new VideoSeekIndexEntry(
lastEntry.StreamIndex,
lastEntry.StreamTimeBase.num,
lastEntry.StreamTimeBase.den,
startTimeTicks,
presentationTime,
decodingTime);
if (entry.StartTime.Ticks > streamDuration.Ticks)
{
return;
}
Entries.Add(entry);
}
}
/// <summary>
/// Loads the specified stream in the CSV-like UTF8 format it was written by the <see cref="Save(Stream)"/> method.
/// </summary>
/// <param name="stream">The stream.</param>
/// <returns>The loaded index from the specified stream.</returns>
public static VideoSeekIndex Load(Stream stream)
{
var separator = new[] { ',' };
var trimQuotes = new[] { '"' };
var result = new VideoSeekIndex(null, -1);
using (var reader = new StreamReader(stream, Encoding.UTF8, true))
{
var state = 0;
while (reader.EndOfStream == false)
{
var line = reader.ReadLine()?.Trim() ?? string.Empty;
if (state == 0 && line == SectionHeaderText)
{
state = 1;
continue;
}
if (state == 1 && line == SectionHeaderFields)
{
state = 2;
continue;
}
if (state == 2 && !string.IsNullOrWhiteSpace(line))
{
var parts = line.Split(separator, 2);
if (parts.Length >= 2)
{
if (int.TryParse(parts[0], out var index))
{
result.StreamIndex = index;
}
result.MediaSource = parts[1]
.Trim(trimQuotes)
.ReplaceOrdinal("\"\"", "\"");
}
state = 3;
}
if (state == 3 && line == SectionDataText)
{
state = 4;
continue;
}
if (state == 4 && line == SectionDataFields)
{
state = 5;
continue;
}
if (state == 5 && !string.IsNullOrWhiteSpace(line))
{
if (VideoSeekIndexEntry.FromCsvString(line) is VideoSeekIndexEntry entry)
{
result.Entries.Add(entry);
}
}
}
}
return(result);
}
