public Atom GetStco(MediaReader reader, Atom track)
{
List <Atom> tracksub = reader.GetAtoms(track.Position + track.HeadLength, track.Size - track.HeadLength).ToList();
Atom mdia = tracksub.FirstOrDefault(m => m.Name == "mdia");
List <Atom> mdiasub = reader.GetAtoms(mdia.Position + mdia.HeadLength, mdia.Size - mdia.HeadLength).ToList();
Atom minf = mdiasub.FirstOrDefault(m => m.Name == "minf");
List <Atom> minfsub = reader.GetAtoms(minf.Position + minf.HeadLength, minf.Size - minf.HeadLength).ToList();
Atom stbl = minfsub.FirstOrDefault(m => m.Name == "stbl");
List <Atom> stblsub = reader.GetAtoms(stbl.Position + stbl.HeadLength, stbl.Size - stbl.HeadLength).ToList();
Atom stco = stblsub.FirstOrDefault(m => m.Name == "stco" || m.Name == "co64");
return(stco);
}
/// <summary>
/// 把moov信息移动到视频信息前端
/// </summary>
/// <param name="newfile">新文件路径</param>
/// <returns>true：移动成功，false：moov信息无需移动</returns>
public bool MoveMoov2Top(string newfile)
{
MediaReader reader = new MediaReader(OriginStream);
List <Atom> atoms = reader.GetAtoms().ToList();
//判断moov和mdata的位置
int moovIndex = 0;
int mdatIndex = 0;
for (int i = 0; i < atoms.Count; i++)
{
Atom atom = atoms[i];
if (atom.Position < 0 || atom.Size < 0)
{
throw new Exception("视频信息异常，视频过大");
}
if (atom.Name == "moov")
{
moovIndex = i;
}
else if (atom.Name == "mdat")
{
mdatIndex = i;
}
}
if (moovIndex == 0 || mdatIndex == 0)
{
throw new Exception("视频信息异常");
}
if (moovIndex < mdatIndex)
{
return(false);
}
//移动
if (atoms[0].Name != "ftyp")
{
throw new Exception("视频信息有异常，ftype位置不对");
}
Atom moov = atoms[moovIndex];
for (int i = moovIndex; i > 1; i--)
{
atoms[i] = atoms[i - 1];
}
atoms[1] = moov;
//Atom temple = atoms[moovIndex];
//atoms[moovIndex] = atoms[mdatIndex];
//atoms[mdatIndex] = temple;
byte[] moovData = reader.ReadData(moov);
List <Atom> moovsub = reader.GetAtoms(moov.Position + moov.HeadLength, moov.Size - moov.HeadLength).ToList();
List <Atom> tracks = moovsub.Where(m => m.Name == "trak").ToList();
List <Atom> stcos = new List <Atom>();
byte[] offsetBytes = new byte[4];
byte[] offset64Bytes = new byte[8];
foreach (var track in tracks)
{
Atom stco = GetStco(reader, track);
byte[] data = reader.ReadDataWithoutHead(stco);
byte[] number_of_entries = new byte[4];
Array.Copy(data, number_of_entries, number_of_entries.Length);
Array.Reverse(number_of_entries);
long length = BitConverter.ToUInt32(number_of_entries, 0);
if (stco.Name == "stco")
{
for (long i = 0; i < length; i++)
{
Array.Copy(data, 4 + 4 * i, offsetBytes, 0, offsetBytes.Length);
Array.Reverse(offsetBytes);
UInt32 offset = BitConverter.ToUInt32(offsetBytes, 0);
offset += (UInt32)moov.Size;
offsetBytes = BitConverter.GetBytes(offset);
Array.Reverse(offsetBytes);
Array.Copy(offsetBytes, 0, moovData, (stco.Position - moov.Position) + stco.HeadLength + 4 + i * 4, offsetBytes.Length);
}
}
else if (stco.Name == "co64")
{
for (long i = 0; i < length; i++)
{
Array.Copy(data, 4 + 8 * i, offset64Bytes, 0, offset64Bytes.Length);
Array.Reverse(offset64Bytes);
long offset = (long)BitConverter.ToUInt64(offset64Bytes, 0);
if (offset < 0)
{
throw new Exception("文件过大");
}
offset += moov.Size;
offset64Bytes = BitConverter.GetBytes(offset);
Array.Reverse(offset64Bytes);
Array.Copy(offset64Bytes, 0, moovData, (stco.Position - moov.Position) + stco.HeadLength + 4 + i * 8, offset64Bytes.Length);
}
}
}
using (FileStream newStream = File.Create(newfile))
{
foreach (Atom atom in atoms)
{
byte[] buffer = null;
if (atom.Name == "moov")
{
buffer = moovData;
}
else
{
buffer = new byte[atom.Size];
OriginStream.Seek(atom.Position, SeekOrigin.Begin);
OriginStream.Read(buffer, 0, buffer.Length);
}
newStream.Write(buffer, 0, buffer.Length);
}
}
return(true);
}
