NSImage SaveToFile(byte_ptrArray4 frame, int width, int height, string file)
{
unsafe {
var rgb = CGColorSpace.CreateDeviceRGB();
var data = frame[0];
//CGBitmapContext
//bitsPerComponent: bytes length of each pixel
//bytesPerRow: image width*channels (RGBA = 4)
//bitmapInfo: bitmap type，the same as destColorFormat (A RGB = PremultipliedFirst, RGB A = PremultipliedLast)
var cgContext = new CGBitmapContext((IntPtr)data, width, height, 8, width * 4, rgb, CGImageAlphaInfo.PremultipliedLast);
var image = cgContext.ToImage();
var imageFinal = new NSImage(image, new CGSize(0, 0));
CMImage.SaveImageToFile(imageFinal, file);
return(imageFinal);
//data = null;
//rgb = null;
//cgContext = null;
//image = null;
//imageFinal = null;
}
}
public List <NSImage> ProcessWithFFmpeg(string path, int thumbnial_width)
{
unsafe {
// FFmpeg test
Console.WriteLine($"FFmpeg version info: {ffmpeg.av_version_info()}");
// setup logging
ffmpeg.av_log_set_level(ffmpeg.AV_LOG_VERBOSE);
av_log_set_callback_callback logCallback = (p0, level, format, vl) =>
{
if (level > ffmpeg.av_log_get_level())
{
return;
}
var lineSize = 1024;
var lineBuffer = stackalloc byte[lineSize];
var printPrefix = 1;
ffmpeg.av_log_format_line(p0, level, format, vl, lineBuffer, lineSize, &printPrefix);
var line = Marshal.PtrToStringAnsi((IntPtr)lineBuffer);
Console.Write(line);
};
ffmpeg.av_log_set_callback(logCallback);
// decode N frames from url or path
//string url = @"../../sample_mpeg4.mp4";
var url = path;
var pFormatContext = ffmpeg.avformat_alloc_context();
int error;
error = ffmpeg.avformat_open_input(&pFormatContext, url, null, null);
if (error != 0)
{
throw new ApplicationException(GetErrorMessage(error));
}
error = ffmpeg.avformat_find_stream_info(pFormatContext, null);
if (error != 0)
{
throw new ApplicationException(GetErrorMessage(error));
}
AVDictionaryEntry *tag = null;
while ((tag = ffmpeg.av_dict_get(pFormatContext->metadata, "", tag, ffmpeg.AV_DICT_IGNORE_SUFFIX)) != null)
{
var key = Marshal.PtrToStringAnsi((IntPtr)tag->key);
var value = Marshal.PtrToStringAnsi((IntPtr)tag->value);
Console.WriteLine($"{key} = {value}");
}
AVStream *pStream = null;
int videoSteam = -1;
for (var i = 0; i < pFormatContext->nb_streams; i++)
{
if (pFormatContext->streams[i]->codec->codec_type == AVMediaType.AVMEDIA_TYPE_VIDEO)
{
pStream = pFormatContext->streams[i];
videoSteam = i;
break;
}
}
if (pStream == null)
{
throw new ApplicationException(@"Could not found video stream.");
}
var codecContext = *pStream->codec;
Console.WriteLine($"codec name: {ffmpeg.avcodec_get_name(codecContext.codec_id)}");
var width = codecContext.width;
var height = codecContext.height;
// Set Thumbnail Size
int tWidth = thumbnial_width;
int tHeight = (int)(thumbnial_width / ((float)width / (float)height));
Console.WriteLine("thumbnail width is {0} and height is {1}", tWidth, tHeight);
var sourcePixFmt = codecContext.pix_fmt;
var codecId = codecContext.codec_id;
var destinationPixFmt = AVPixelFormat.AV_PIX_FMT_RGBA;
var pConvertContext = ffmpeg.sws_getContext(width, height, sourcePixFmt,
tWidth, tHeight, destinationPixFmt,
ffmpeg.SWS_BILINEAR, null, null, null);
if (pConvertContext == null)
{
throw new ApplicationException(@"Could not initialize the conversion context.");
}
var pConvertedFrame = ffmpeg.av_frame_alloc();
var convertedFrameBufferSize = ffmpeg.av_image_get_buffer_size(destinationPixFmt, tWidth, tHeight, 1);
var convertedFrameBufferPtr = Marshal.AllocHGlobal(convertedFrameBufferSize);
var dstData = new byte_ptrArray4();
var dstLinesize = new int_array4();
ffmpeg.av_image_fill_arrays(ref dstData, ref dstLinesize, (byte *)convertedFrameBufferPtr, destinationPixFmt, tWidth, tHeight, 1);
var pCodec = ffmpeg.avcodec_find_decoder(codecId);
if (pCodec == null)
{
throw new ApplicationException(@"Unsupported codec.");
}
var pCodecContext = &codecContext;
if ((pCodec->capabilities & ffmpeg.AV_CODEC_CAP_TRUNCATED) == ffmpeg.AV_CODEC_CAP_TRUNCATED)
{
pCodecContext->flags |= ffmpeg.AV_CODEC_FLAG_TRUNCATED;
}
error = ffmpeg.avcodec_open2(pCodecContext, pCodec, null);
if (error < 0)
{
throw new ApplicationException(GetErrorMessage(error));
}
var pDecodedFrame = ffmpeg.av_frame_alloc();
var packet = new AVPacket();
var pPacket = &packet;
ffmpeg.av_init_packet(pPacket);
// Calculate Time interval for Frame
AVRational relation = new AVRational()
{
num = 1,
den = ffmpeg.AV_TIME_BASE
};
var frameNumber = 24;
long duration = ffmpeg.av_rescale_q(pFormatContext->duration, relation, pStream->time_base);
double interval = duration / (double)frameNumber;
var timebase = pStream->time_base;
double timebaseDouble = timebase.num / timebase.den;
int count = 0;
var thumbnails = new List <NSImage>();
while (count <= frameNumber)
{
long seek_pos = Convert.ToInt64(interval * count + pStream->start_time);
ffmpeg.avcodec_flush_buffers(pCodecContext);
error = ffmpeg.av_seek_frame(pFormatContext, videoSteam, seek_pos, ffmpeg.AVSEEK_FLAG_BACKWARD);
if (error < 0)
{
throw new ApplicationException(GetErrorMessage(error));
}
ffmpeg.avcodec_flush_buffers(pCodecContext);
Console.WriteLine("Frame seek pos {0} {1}", seek_pos, count);
while ((error = ffmpeg.av_read_frame(pFormatContext, pPacket)) >= 0)
{
if (packet.stream_index == videoSteam)
{
Console.WriteLine("Process frame {0}", count);
error = ffmpeg.avcodec_send_packet(pCodecContext, pPacket);
if (error < 0)
{
throw new ApplicationException(GetErrorMessage(error));
}
error = ffmpeg.avcodec_receive_frame(pCodecContext, pDecodedFrame);
if (error == ffmpeg.AVERROR(35))
{
continue;
}
if (error < 0)
{
throw new ApplicationException(GetErrorMessage(error));
}
Console.WriteLine($@"frame: {count}");
ffmpeg.sws_scale(pConvertContext, pDecodedFrame->data, pDecodedFrame->linesize, 0, height, dstData, dstLinesize);
var image = SaveToFile(dstData, tWidth, tHeight, $@"{count}.tiff");
thumbnails.Add(image);
count++;
break;
}
ffmpeg.av_packet_unref(pPacket);
ffmpeg.av_frame_unref(pDecodedFrame);
}
}
Marshal.FreeHGlobal(convertedFrameBufferPtr);
ffmpeg.av_free(pConvertedFrame);
ffmpeg.sws_freeContext(pConvertContext);
ffmpeg.av_free(pDecodedFrame);
ffmpeg.avcodec_close(pCodecContext);
ffmpeg.avformat_close_input(&pFormatContext);
return(thumbnails);
}
}
