obs-qsv: Enable B-frames and B-pyramid for encoder

Enable B-Pyramid frames to improve quality for high motion content.
B-pyramid allows a B-frame to choose closer frames for reference which
may have higher correlation.

Adjusts packet priority to avoid dropping referable B-frames

A check has been added to ensure feature is enabled only on platforms
with MSDK API 1.8 or higher - addresses crashing issues.

plugins/obs-qsv11/QSV_Encoder_Internal.cpp

@@ -209,6 +209,7 @@ bool QSV_Encoder_Internal::InitParams(qsv_param_t *pParams)
 	m_mfxEncParams.mfx.FrameInfo.CropY = 0;
 	m_mfxEncParams.mfx.FrameInfo.CropW = pParams->nWidth;
 	m_mfxEncParams.mfx.FrameInfo.CropH = pParams->nHeight;
+	m_mfxEncParams.mfx.GopRefDist = pParams->nbFrames + 1;
 
 	m_mfxEncParams.mfx.RateControlMethod = pParams->nRateControl;
 
@@ -253,23 +254,23 @@ bool QSV_Encoder_Internal::InitParams(qsv_param_t *pParams)
 	int iBuffers = 0;
 	if (pParams->nAsyncDepth == 1) {
 		m_mfxEncParams.mfx.NumRefFrame = 1;
-		// low latency, I and P frames only
-		m_mfxEncParams.mfx.GopRefDist = 1;
 		memset(&m_co, 0, sizeof(mfxExtCodingOption));
 		m_co.Header.BufferId = MFX_EXTBUFF_CODING_OPTION;
 		m_co.Header.BufferSz = sizeof(mfxExtCodingOption);
 		m_co.MaxDecFrameBuffering = 1;
 		extendedBuffers[iBuffers++] = (mfxExtBuffer *)&m_co;
-	} else
-		m_mfxEncParams.mfx.GopRefDist = pParams->nbFrames + 1;
-
-	if (pParams->nRateControl == MFX_RATECONTROL_LA_ICQ ||
-	    pParams->nRateControl == MFX_RATECONTROL_LA) {
+	}
 
+	if (m_ver.Major == 1 && m_ver.Minor >= 8)
+	{
 		memset(&m_co2, 0, sizeof(mfxExtCodingOption2));
-		m_co2.Header.BufferId = MFX_EXTBUFF_CODING_OPTION;
+		m_co2.Header.BufferId = MFX_EXTBUFF_CODING_OPTION2;
 		m_co2.Header.BufferSz = sizeof(m_co2);
-		m_co2.LookAheadDepth = pParams->nLADEPTH;
+		if (pParams->nRateControl == MFX_RATECONTROL_LA_ICQ ||
+		    pParams->nRateControl == MFX_RATECONTROL_LA)
+			m_co2.LookAheadDepth = pParams->nLADEPTH;
+		if (pParams->nbFrames > 1)
+			m_co2.BRefType = MFX_B_REF_PYRAMID;
 		extendedBuffers[iBuffers++] = (mfxExtBuffer *)&m_co2;
 	}
 

plugins/obs-qsv11/obs-qsv11.c

@@ -158,6 +158,7 @@ static void obs_qsv_defaults(obs_data_t *settings)
 	obs_data_set_default_int(settings, "la_depth", 40);
 
 	obs_data_set_default_int(settings, "keyint_sec", 3);
+	obs_data_set_default_int(settings, "bframes", 3);
 }
 
 static inline void add_strings(obs_property_t *list, const char *const *strings)
@@ -179,6 +180,7 @@ static inline void add_strings(obs_property_t *list, const char *const *strings)
 #define TEXT_ICQ_QUALITY obs_module_text("ICQQuality")
 #define TEXT_LA_DEPTH obs_module_text("LookAheadDepth")
 #define TEXT_KEYINT_SEC obs_module_text("KeyframeIntervalSec")
+#define TEXT_BFRAMES obs_module_text("B Frames")
 
 static bool rate_control_modified(obs_properties_t *ppts, obs_property_t *p,
 				  obs_data_t *settings)
@@ -279,6 +281,7 @@ static obs_properties_t *obs_qsv_props(void *unused)
 	obs_properties_add_int(props, "icq_quality", TEXT_ICQ_QUALITY, 1, 51,
 			       1);
 	obs_properties_add_int(props, "la_depth", TEXT_LA_DEPTH, 10, 100, 1);
+	obs_properties_add_int(props, "bframes", TEXT_BFRAMES, 0, 3, 1);
 
 	return props;
 }
@@ -305,7 +308,7 @@ static void update_params(struct obs_qsv *obsqsv, obs_data_t *settings)
 	int la_depth = (int)obs_data_get_int(settings, "la_depth");
 	int keyint_sec = (int)obs_data_get_int(settings, "keyint_sec");
 	bool cbr_override = obs_data_get_bool(settings, "cbr");
-	int bFrames = 7;
+	int bFrames = (int)obs_data_get_int(settings, "bframes");
 
 	if (obs_data_has_user_value(settings, "bf"))
 		bFrames = (int)obs_data_get_int(settings, "bf");
@@ -611,8 +614,19 @@ static void parse_packet(struct obs_qsv *obsqsv, struct encoder_packet *packet,
 	packet->size = obsqsv->packet_data.num;
 	packet->type = OBS_ENCODER_VIDEO;
 	packet->pts = pBS->TimeStamp * fps_num / 90000;
-	packet->keyframe =
-		(pBS->FrameType & (MFX_FRAMETYPE_I | MFX_FRAMETYPE_REF));
+	packet->keyframe = (pBS->FrameType & MFX_FRAMETYPE_IDR);
+
+	uint16_t frameType = pBS->FrameType;
+	uint8_t priority;
+
+	if (frameType & MFX_FRAMETYPE_I)
+		priority = OBS_NAL_PRIORITY_HIGHEST;
+	else if ((frameType & MFX_FRAMETYPE_P) || (frameType & MFX_FRAMETYPE_REF))
+		priority = OBS_NAL_PRIORITY_HIGH;
+	else
+		priority = 0;
+
+	packet->priority = priority;
 
 	/* ------------------------------------ */
 
@@ -629,15 +643,8 @@ static void parse_packet(struct obs_qsv *obsqsv, struct encoder_packet *packet,
 
 		type = start[0] & 0x1F;
 		if (type == OBS_NAL_SLICE_IDR || type == OBS_NAL_SLICE) {
-			uint8_t prev_type = (start[0] >> 5) & 0x3;
 			start[0] &= ~(3 << 5);
-
-			if (pBS->FrameType & MFX_FRAMETYPE_I)
-				start[0] |= OBS_NAL_PRIORITY_HIGHEST << 5;
-			else if (pBS->FrameType & MFX_FRAMETYPE_P)
-				start[0] |= OBS_NAL_PRIORITY_HIGH << 5;
-			else
-				start[0] |= prev_type << 5;
+			start[0] |= priority << 5; //0 for non-ref frames and not equal to 0 for ref frames
 		}
 
 		start = (uint8_t *)obs_avc_find_startcode(start, end);