Revert "HDR: Remove unused code in FFmpegController"

This reverts commit 4b5f0b9.

iina/FFmpegController.h

@@ -43,4 +43,7 @@
 
 + (nullable NSDictionary *)probeVideoInfoForFile:(nonnull NSString *)file;
 
+// HDR
++ (nullable NSDictionary *)getColorSpaceMetadataForFile:(nonnull NSString *)file;
+
 @end

iina/FFmpegController.m

@@ -283,6 +283,7 @@ - (int)getPeeksForFile:(NSString *)file
   return 0;
 }
 
+
 - (void)saveThumbnail:(AVFrame *)pFrame width
                      :(int)width height
                      :(int)height index
@@ -330,6 +331,179 @@ - (void)saveThumbnail:(AVFrame *)pFrame width
   }
 }
 
+// HDR
+// Backward conversion from primaries metadata to color space is taken from here
+// https://github.com/rigaya/NVEnc/issues/51#issuecomment-392572746
+// Also from File__Analyze_Streams.cpp in MediaInfo
+
+struct masteringdisplaycolorvolume_values
+{
+    int Code; //ISO code
+    double Values[8]; // G, B, R, W pairs (x values then y values)
+};
+static const int MasteringDisplayColorVolume_Values_Size=4;
+static const struct masteringdisplaycolorvolume_values MasteringDisplayColorVolume_Values[] =
+{
+    { 1, {15000, 30000,  7500,  3000, 32000, 16500, 15635, 16450}}, // BT.709
+    { 9, { 8500, 39850,  6550,  2300, 35400, 14600, 15635, 16450}}, // BT.2020
+    {11, {13250, 34500,  7500,  3000, 34000, 16000, 15700, 17550}}, // DCI P3
+    {12, {13250 /*green_x*/, 34500 /*green_y*/,  7500 /*blue_x*/,  3000 /*blue_y*/, 34000 /*red_x*/, 16000 /*red_y*/, /* whitepoint_x */ 15635, /* whitepoint_y */ 16450}}, // Display P3
+};
+
+static inline double avr2d(AVRational a) {
+  return (double)a.num / (double)a.den;
+}
+
++ (NSDictionary *)getColorSpaceMetadataForFile:(nonnull NSString *)file
+{
+  int ret;
+  AVFormatContext *pFormatCtx = NULL;
+  AVCodecContext *pCodecCtx = NULL;
+  AVFrame *pFrame = NULL;
+
+  @try {
+    char *cFilename = strdup(file.fileSystemRepresentation);
+    ret = avformat_open_input(&pFormatCtx, cFilename, NULL, NULL);
+    free(cFilename);
+    if (ret < 0) return NULL;
+
+    ret = avformat_find_stream_info(pFormatCtx, NULL);
+    if (ret < 0) return NULL;
+
+    int videoStream = av_find_best_stream(pFormatCtx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
+    if (videoStream < 0) return NULL;
+
+    // Get the codec context for the video stream
+    AVStream *pVideoStream = pFormatCtx->streams[videoStream];
+
+    NSMutableDictionary *info = [[NSMutableDictionary alloc] init];
+
+    switch (pVideoStream->codecpar->color_trc)
+    {
+      // ITU-R BT.2100 HLG (Hybrid Log-gamma) curve, aka ARIB STD-B67
+      case AVCOL_TRC_ARIB_STD_B67: info[@"color-trc"] = @"hlg"; break;
+      // ITU-R BT.2100 PQ (Perceptual quantizer) curve, aka SMPTE ST2084
+      // assuming that AVCOL_TRC_SMPTEST2084 and AVCOL_TRC_SMPTE2084 have same value
+      case AVCOL_TRC_SMPTE2084: info[@"color-trc"] = @"pq"; break;
+
+      default: return NULL; // SDR content
+    }
+
+    AVMasteringDisplayMetadata *metadata = (AVMasteringDisplayMetadata *)av_stream_get_side_data(pVideoStream, AV_PKT_DATA_MASTERING_DISPLAY_METADATA, NULL);
+
+    if (!metadata) {
+      // Find the decoder for the video stream
+      AVCodec *pCodec = avcodec_find_decoder(pVideoStream->codecpar->codec_id);
+      if (!pCodec) return NULL;
+
+      // Open codec
+      pCodecCtx = avcodec_alloc_context3(pCodec);
+      if (!pCodecCtx) return NULL;
+
+      ret = avcodec_parameters_to_context(pCodecCtx, pVideoStream->codecpar);
+      if (ret < 0) return NULL;
+
+      ret = avcodec_open2(pCodecCtx, pCodec, NULL);
+      if (ret < 0) return NULL;
+
+      AVPacket packet;
+      while (av_read_frame(pFormatCtx, &packet) >= 0) {
+        if (packet.stream_index != videoStream) continue;
+        ret = avcodec_send_packet(pCodecCtx, &packet);
+        if (ret < 0) break;
+
+        metadata = (AVMasteringDisplayMetadata *)av_packet_get_side_data(&packet, AV_PKT_DATA_MASTERING_DISPLAY_METADATA, NULL);
+        if (metadata) break;
+
+        pFrame = av_frame_alloc();
+        ret = avcodec_receive_frame(pCodecCtx, pFrame);
+        if (ret < 0) {
+          if (ret == AVERROR(EAGAIN)) continue;
+          break;
+        }
+
+        AVFrameSideData* side_data = av_frame_get_side_data(pFrame, AV_FRAME_DATA_MASTERING_DISPLAY_METADATA);
+
+        if(side_data) metadata = (AVMasteringDisplayMetadata *) side_data->data;
+        break;
+      }
+    }
+
+    if (metadata && metadata->has_primaries)
+    {
+      int code = -1;
+      for (int i=0; i<MasteringDisplayColorVolume_Values_Size; i++)
+      {
+        const struct masteringdisplaycolorvolume_values* values = &MasteringDisplayColorVolume_Values[i];
+        int j = 0;
+
+        // +/- 0.0005 (3 digits after comma)
+        double gValue = avr2d(metadata->display_primaries[1][0]) / 0.00002;
+        if (gValue<values->Values[0*2+j]-25 || gValue>=values->Values[0*2+j]+25)
+          continue;
+        double bValue = avr2d(metadata->display_primaries[2][0]) / 0.00002;
+        if (bValue<values->Values[1*2+j]-25 || bValue>=values->Values[1*2+j]+25)
+          continue;
+        double rValue = avr2d(metadata->display_primaries[0][0]) / 0.00002;
+        if (rValue<values->Values[2*2+j]-25 || rValue>=values->Values[2*2+j]+25)
+          continue;
+
+        // +/- 0.00005 (4 digits after comma)
+        double wpValue = avr2d(metadata->white_point[0]) / 0.00002;
+        if (wpValue<values->Values[3*2+j]-2 || wpValue>=values->Values[3*2+j]+3)
+          continue;
+
+        code = values->Code;
+        break;
+      }
+
+      switch (code)
+      {
+        case 9: info[@"primaries"] = @"bt.2020"; break;
+        case 11: info[@"primaries"] = @"dci-p3"; break;
+        case 12: info[@"primaries"] = @"display-p3"; break;
+
+        case 1: // bt709. The source may not be correctly encoded, ignoring...
+        default:
+          break;
+      }
+    }
+
+    if (!info[@"primaries"]) {
+      NSLog(@"HDR: Video source doesn't provide master display metadata");
+
+      switch (pVideoStream->codecpar->color_primaries) {
+        case AVCOL_PRI_SMPTE432: info[@"primaries"] = @"display-p3"; break;
+        case AVCOL_PRI_SMPTE431: info[@"primaries"] = @"dci-p3"; break;
+        case AVCOL_PRI_BT2020: default: info[@"primaries"] = @"bt.2020"; break;
+      }
+    }
+
+    if (metadata && metadata->has_luminance)
+    {
+      double max_luminance = avr2d(metadata->max_luminance);
+      info[@"max_luminance"] = [NSNumber numberWithDouble:max_luminance];
+      double min_luminance = avr2d(metadata->min_luminance);
+      info[@"min_luminance"] = [NSNumber numberWithDouble:min_luminance];
+    }
+
+    NSLog(@"HDR: primaries=%@ color-trc=%@ max_luminance=%@", info[@"primaries"], info[@"color-trc"], info[@"max_luminance"]);
+
+    return info;
+  } @finally {
+    if (pFrame) {
+      av_frame_free(&pFrame);
+    }
+    if (pCodecCtx) {
+      avcodec_free_context(&pCodecCtx);
+    }
+    if (pFormatCtx) {
+      avformat_close_input(&pFormatCtx);
+      avformat_free_context(pFormatCtx);
+    }
+  }
+}
+
 + (NSDictionary *)probeVideoInfoForFile:(nonnull NSString *)file
 {
   int ret;