text: /*
  	MIT License
  
  	Copyright (c) 2016 Błażej Szczygieł
  
  	Permission is hereby granted, free of charge, to any person obtaining a copy
  	of this software and associated documentation files (the "Software"), to deal
  	in the Software without restriction, including without limitation the rights
  	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  	copies of the Software, and to permit persons to whom the Software is
  	furnished to do so, subject to the following conditions:
  
  	The above copyright notice and this permission notice shall be included in all
  	copies or substantial portions of the Software.
  
  	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  	SOFTWARE.
  */
  
  #include "VPXDecoder.hpp"
  
  #include <vpx/vpx_decoder.h>
  #include <vpx/vp8dx.h>
  
  #include <stdlib.h>
  #include <string.h>
  
  VPXDecoder::VPXDecoder(const WebMDemuxer &demuxer, unsigned threads) :
  	m_ctx(NULL),
  	m_iter(NULL),
  	m_delay(0),
  	m_last_space(VPX_CS_UNKNOWN)
  {
  	if (threads > 8)
  		threads = 8;
  	else if (threads < 1)
  		threads = 1;
  
  	const vpx_codec_dec_cfg_t codecCfg = {
  		threads,
  		0,
  		0
  	};
  	vpx_codec_iface_t *codecIface = NULL;
  
  	switch (demuxer.getVideoCodec())
  	{
  		case WebMDemuxer::VIDEO_VP8:
  			codecIface = vpx_codec_vp8_dx();
  			break;
  		case WebMDemuxer::VIDEO_VP9:
  			codecIface = vpx_codec_vp9_dx();
  			m_delay = threads - 1;
  			break;
  		default:
  			return;
  	}
  
  	m_ctx = new vpx_codec_ctx_t;
  	if (vpx_codec_dec_init(m_ctx, codecIface, &codecCfg, m_delay > 0 ? VPX_CODEC_USE_FRAME_THREADING : 0))
  	{
  		delete m_ctx;
  		m_ctx = NULL;
  	}
  }
  VPXDecoder::~VPXDecoder()
  {
  	if (m_ctx)
  	{
  		vpx_codec_destroy(m_ctx);
  		delete m_ctx;
  	}
  }
  
  bool VPXDecoder::decode(const WebMFrame &frame)
  {
  	m_iter = NULL;
  	return !vpx_codec_decode(m_ctx, frame.buffer, frame.bufferSize, NULL, 0);
  }
  VPXDecoder::IMAGE_ERROR VPXDecoder::getImage(Image &image)
  {
  	IMAGE_ERROR err = NO_FRAME;
  	if (vpx_image_t *img = vpx_codec_get_frame(m_ctx, &m_iter))
  	{
  		// It seems to be a common problem that UNKNOWN comes up a lot, yet FFMPEG is somehow getting accurate colour-space information.
  		// After checking FFMPEG code, *they're* getting colour-space information, so I'm assuming something like this is going on.
  		// It appears to work, at least.
  		if (img->cs != VPX_CS_UNKNOWN)
  			m_last_space = img->cs;
  		if ((img->fmt & VPX_IMG_FMT_PLANAR) && !(img->fmt & VPX_IMG_FMT_HIGHBITDEPTH))
  		{
  			if (img->stride[0] && img->stride[1] && img->stride[2])
  			{
  				const int yPlane = VPX_PLANE_Y;
  				const int uPlane = !!(img->fmt & VPX_IMG_FMT_UV_FLIP) + 1;
  				const int vPlane =  !(img->fmt & VPX_IMG_FMT_UV_FLIP) + 1;
  				const int aPlane = VPX_PLANE_ALPHA;
  
  				image.w = img->d_w;
  				image.h = img->d_h;
  				image.cs = m_last_space;
  				image.chromaShiftW = img->x_chroma_shift;
  				image.chromaShiftH = img->y_chroma_shift;
  
  				image.planes[0] = img->planes[yPlane];
  				image.planes[1] = img->planes[uPlane];
  				image.planes[2] = img->planes[vPlane];
  				image.planes[3] = img->planes[aPlane];
  
  				image.linesize[0] = img->stride[yPlane];
  				image.linesize[1] = img->stride[uPlane];
  				image.linesize[2] = img->stride[vPlane];
  				image.linesize[3] = img->stride[aPlane];
  				image.imgdata = img->img_data;
  				err = NO_ERROR;
  			}
  		}
  		else
  		{
  			err = UNSUPPORTED_FRAME;
  		}
  	}
  	return err;
  }
  
  /**/
  
  static inline int ceilRshift(int val, int shift)
  {
  	return (val + (1 << shift) - 1) >> shift;
  }
  
  int VPXDecoder::Image::getWidth(int plane) const
  {
  	if (!plane)
  		return w;
  	return ceilRshift(w, chromaShiftW);
  }
  int VPXDecoder::Image::getHeight(int plane) const
  {
  	if (!plane)
  		return h;
  	return ceilRshift(h, chromaShiftH);
  }
  