FFMPEG Plugin: Implement and use calculation of bytes per row.

src/add-ons/media/plugins/ffmpeg/AVCodecDecoder.cpp

@@ -908,7 +908,9 @@ AVCodecDecoder::_UpdateMediaHeaderForVideoFrame()
 	fHeader.start_time = fRawDecodedPicture->reordered_opaque;
 	fHeader.u.raw_video.display_line_width = fRawDecodedPicture->width;
 	fHeader.u.raw_video.display_line_count = fRawDecodedPicture->height;
-	fHeader.u.raw_video.bytes_per_row = 0; // TODO: Implement calculation
+	fHeader.u.raw_video.bytes_per_row
+		= CalculateBytesPerRowWithColorSpaceAndVideoWidth(
+			fOutputVideoFormat.display.format, fRawDecodedPicture->width);
 	fHeader.u.raw_video.field_gamma = 1.0;
 	fHeader.u.raw_video.field_sequence = fFrame;
 	fHeader.u.raw_video.field_number = 0;

src/add-ons/media/plugins/ffmpeg/Utilities.h

@@ -7,13 +7,15 @@
 #define UTILITIES_H
 
 
-/*! \brief This file contains functions to convert values from FFmpeg to Media
+/*! \brief This file contains functions to convert and calculate values from
-		Kit and vice versa.
+		FFmpeg to Media Kit and vice versa.
 */
 
 
 #include <assert.h>
 
+#include <GraphicsDefs.h>
+
 extern "C" {
 	#include "avcodec.h"
 }
@@ -70,5 +72,37 @@ ConvertAVCodecContextToVideoAspectWidthAndHeight(AVCodecContext& contextIn,
 }
 
 
+/*! \brief Calculates bytes per row for a video frame.
+
+	\param colorSpace The Media Kit color space the video frame uses.
+	\param videoWidth The width of the video frame.
+
+	\returns bytes per video frame row
+	\returns Zero, when bytes per video frame cannot be calculated.
+*/
+inline uint32
+CalculateBytesPerRowWithColorSpaceAndVideoWidth(color_space colorSpace, int videoWidth)
+{
+	assert(videoWidth >= 0);
+
+	const uint32 kBytesPerRowUnknown = 0;
+	size_t bytesPerPixel;
+	size_t rowAlignment;
+
+	if (get_pixel_size_for(colorSpace, &bytesPerPixel, &rowAlignment, NULL) != B_OK)
+		return kBytesPerRowUnknown;
+
+	uint32 bytesPerRow = bytesPerPixel * videoWidth;
+	uint32 numberOfUnalignedBytes = bytesPerRow % rowAlignment;
+
+	if (numberOfUnalignedBytes == 0)
+		return bytesPerRow;
+
+	uint32 numberOfBytesNeededForAlignment = rowAlignment - numberOfUnalignedBytes;
+	bytesPerRow += numberOfBytesNeededForAlignment;
+
+	return bytesPerRow;
+}
+
 
 #endif // UTILITIES_H