public bool NextVideoFrame(IntPtr target, FFmpeg.PixelFormat desiredFormat, ref double time)
{
if (!hasVideo)
{
return(false);
}
int got_picture = 0;
long pts = -1;
// Allocate video frame
vFrame = FFmpeg.avcodec_alloc_frame();
// Decode packets until we've got a full frame
while (got_picture == 0)
{
// If we need a new packet, get it
if (vPacket.size <= 0)
{
if (vPacket.data != IntPtr.Zero)
{
FFmpeg.av_free_packet(vPacket.priv);
}
lock (locker)
{
// If there are no more packets in the queue, read them from stream
while (videoPacketQueue.Count < 1)
{
if (!ReadPacket())
{
return(false);
}
}
vPacket = videoPacketQueue.Dequeue();
}
}
// Do nothing if timing is too early
if (pts == -1)
{
pts = vPacket.pts;
if (pts * videoTimebase > time)
{
time = pts * videoTimebase - time;
return(true);
}
time = 0;
}
// Decode packet
int length = FFmpeg.avcodec_decode_video(videoStream.codec, vFrame, ref got_picture, vPacket.data, vPacket.size);
// Error, skip packet
if (length < 0)
{
vPacket.size = 0;
continue;
}
// Move forward in packet
vPacket.data = new IntPtr(vPacket.data.ToInt64() + length);
vPacket.size -= length;
}
// Create RGB frame
IntPtr rgbFrame = FFmpeg.avcodec_alloc_frame();
FFmpeg.avpicture_fill(rgbFrame, target, (int)desiredFormat, width, height);
// Convert video frame to RGB
FFmpeg.img_convert(rgbFrame, (int)desiredFormat, vFrame, (int)originalVideoFormat, width, height);
// Free memory
FFmpeg.av_free(rgbFrame);
FFmpeg.av_free(vFrame);
return(true);
}
public MediaFile(Stream inStream)
{
// Create unique name
string filename = "stream://" + counter;
// Register stream
streams.Add(filename, inStream);
// Open stream with FFmpeg
if (FFmpeg.av_open_input_file(out pFormatContext, filename, IntPtr.Zero, 0, IntPtr.Zero) < 0)
{
throw new Exception("Unable to open stream");
}
// Get context
FFmpeg.AVFormatContext formatContext = PtrToStructure <FFmpeg.AVFormatContext>(pFormatContext);
// Get stream info
if (FFmpeg.av_find_stream_info(pFormatContext) < 0)
{
throw new Exception("Unable to find stream info");
}
// Loop through streams in this file
for (int i = 0; i < formatContext.nb_streams; ++i)
{
FFmpeg.AVStream stream = PtrToStructure <FFmpeg.AVStream>(formatContext.streams[i]);
FFmpeg.AVCodecContext codecContext = PtrToStructure <FFmpeg.AVCodecContext>(stream.codec);
// Get codec
IntPtr pCodec = FFmpeg.avcodec_find_decoder(codecContext.codec_id);
FFmpeg.AVCodec codec = PtrToStructure <FFmpeg.AVCodec>(pCodec);
if (pCodec == IntPtr.Zero)
{
continue;
}
// Check codec type
bool open = false;
switch (codecContext.codec_type)
{
case FFmpeg.CodecType.CODEC_TYPE_AUDIO:
// We only need 1 audio stream
if (hasAudio)
{
break;
}
// Get stream information
hasAudio = true;
numChannels = codecContext.channels;
audioDepth = (codecContext.sample_fmt == FFmpeg.SampleFormat.SAMPLE_FMT_U8) ? 8 : 16;
frequency = codecContext.sample_rate;
audioStream = stream;
audioTimebase = (double)stream.time_base.num / (double)stream.time_base.den;
open = true;
break;
case FFmpeg.CodecType.CODEC_TYPE_VIDEO:
// We only need 1 video stream
if (hasVideo)
{
break;
}
// Set codec flags
if ((codec.capabilities & FFmpeg.CODEC_CAP_TRUNCATED) != 0)
{
codecContext.flags = codecContext.flags | FFmpeg.CODEC_FLAG_TRUNCATED;
}
// Get stream information
hasVideo = true;
width = codecContext.width;
height = codecContext.height;
videoStream = stream;
originalVideoFormat = codecContext.pix_fmt;
videoTimebase = (double)codecContext.time_base.num / (double)codecContext.time_base.den;
open = true;
break;
}
// Update codec context
Marshal.StructureToPtr(codecContext, stream.codec, false);
// Open codec
if (open)
{
if (FFmpeg.avcodec_open(stream.codec, pCodec) < 0)
{
throw new Exception("Unable to open codec");
}
}
}
// No video or audio found
if (!hasAudio && !hasVideo)
{
throw new Exception("No codecs or streams found");
}
}
