public unsafe H264Decoder(List <byte[]> nalUnits)
{
if (!initialized)
{
ffmpeg.av_register_all();
initialized = true;
}
int localStreamSuffix = streamSuffix;
streamSuffix++;
int dataSize = 0;
foreach (byte[] nalUnit in nalUnits)
{
dataSize += nalUnit.Length + startSequence.Length;
}
byte *dat = (byte *)ffmpeg.av_malloc((ulong)dataSize);
fixed(byte *start = startSequence)
{
foreach (byte[] nalUnit in nalUnits)
{
fixed(byte *dataPtr = nalUnit)
{
UnmanagedMemory.CopyMemory(dat, start, (uint)startSequence.Length);
dat += startSequence.Length;
UnmanagedMemory.CopyMemory(dat, dataPtr, (uint)nalUnit.Length);
dat += nalUnit.Length;
}
}
dat -= dataSize;
}
AVFormatContext *icLocal = ffmpeg.avformat_alloc_context();
ic = icLocal;
avio_alloc_context_write_packet_func writeCallback;
writeCallback.Pointer = IntPtr.Zero;
avio_alloc_context_seek_func seekCallback;
seekCallback.Pointer = IntPtr.Zero;
avio_alloc_context_read_packet_func readCallback;
readCallback.Pointer = IntPtr.Zero;
icLocal->pb = ffmpeg.avio_alloc_context(dat, bufferSize, 0, null, readCallback, writeCallback, seekCallback);
if (icLocal->pb == null)
{
throw new Exception("Failed to allocate ffmpeg context.");
}
// Need to probe buffer for input format unless you already know it
AVProbeData probe_data;
probe_data.buf_size = dataSize;
probe_data.filename = (byte *)Marshal.StringToHGlobalAnsi($"stream_{localStreamSuffix}");
probe_data.buf = (byte *)UnmanagedMemory.Alloc(probe_data.buf_size);
UnmanagedMemory.CopyMemory(probe_data.buf, dat, (uint)probe_data.buf_size);
AVInputFormat *pAVInputFormat = ffmpeg.av_probe_input_format(&probe_data, 1);
if (pAVInputFormat == null)
{
pAVInputFormat = ffmpeg.av_probe_input_format(&probe_data, 0);
}
// cleanup
UnmanagedMemory.DeAlloc((IntPtr)probe_data.buf, probe_data.buf_size);
probe_data.buf = null;
pAVInputFormat->flags |= ffmpeg.AVFMT_NOFILE;
ffmpeg.avformat_open_input(&icLocal, $"stream_{localStreamSuffix}", pAVInputFormat, null);
for (int i = 0; i < icLocal->nb_streams; i++)
{
AVCodecContext *enc = icLocal->streams[i]->codec;
if (AVMediaType.AVMEDIA_TYPE_VIDEO == enc->codec_type)
{
AVCodec *codec = ffmpeg.avcodec_find_decoder(enc->codec_id);
if (codec == null || ffmpeg.avcodec_open2(enc, codec, null) < 0)
{
//Console.WriteLine("Cannot find codec");
}
video_st = icLocal->streams[i];
}
}
//Init picture
yuv_image = ffmpeg.av_frame_alloc();
yuv_image->format = -1; //We do not know the format of the raw decoded image
}