qsv: Support explicit lookahead downscaling

libavcodec/qsvenc.c

@@ -604,6 +604,10 @@ FF_ENABLE_DEPRECATION_WARNINGS
             q->extco2.Trellis = q->trellis;
 #endif
 
+#if QSV_HAVE_LA_DS
+            q->extco2.LookAheadDS = q->la_ds;
+#endif
+
 #if QSV_HAVE_BREF_TYPE
 #if FF_API_PRIVATE_OPT
 FF_DISABLE_DEPRECATION_WARNINGS

libavcodec/qsvenc.h

@@ -42,6 +42,7 @@
 #define QSV_HAVE_BREF_TYPE      QSV_VERSION_ATLEAST(1, 8)
 
 #define QSV_HAVE_LA     QSV_VERSION_ATLEAST(1, 7)
+#define QSV_HAVE_LA_DS  QSV_VERSION_ATLEAST(1, 8)
 #define QSV_HAVE_LA_HRD QSV_VERSION_ATLEAST(1, 11)
 
 #if defined(_WIN32)
@@ -54,6 +55,12 @@
 #define QSV_HAVE_QVBR   0
 #endif
 
+#if !QSV_HAVE_LA_DS
+#define MFX_LOOKAHEAD_DS_OFF 0
+#define MFX_LOOKAHEAD_DS_2x 0
+#define MFX_LOOKAHEAD_DS_4x 0
+#endif
+
 #define QSV_COMMON_OPTS \
 { "async_depth", "Maximum processing parallelism", OFFSET(qsv.async_depth), AV_OPT_TYPE_INT, { .i64 = ASYNC_DEPTH_DEFAULT }, 0, INT_MAX, VE },  \
 { "avbr_accuracy",    "Accuracy of the AVBR ratecontrol",    OFFSET(qsv.avbr_accuracy),    AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, VE },     \
@@ -64,6 +71,11 @@
 { "slow",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = MFX_TARGETUSAGE_BEST_QUALITY  }, INT_MIN, INT_MAX, VE, "preset" },                             \
 { "la_depth", "Number of frames to analyze before encoding.", OFFSET(qsv.la_depth), AV_OPT_TYPE_INT, { .i64 = 9 },   9, 100, VE, "la_depth" },  \
 { "unset", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 9 }, INT_MIN, INT_MAX,                                                       VE, "la_depth" },  \
+{ "la_ds", "Downscaling factor for the frames saved for the lookahead analysis", OFFSET(qsv.la_ds), AV_OPT_TYPE_INT, { .i64 = -1 },   -1, MFX_LOOKAHEAD_DS_4x, VE, "la_ds" }, \
+{ "auto", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = -1 }, INT_MIN, INT_MAX,                                                           VE, "la_ds" }, \
+{ "off", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = MFX_LOOKAHEAD_DS_OFF }, INT_MIN, INT_MAX,                                          VE, "la_ds" }, \
+{ "2x", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = MFX_LOOKAHEAD_DS_2x }, INT_MIN, INT_MAX,                                            VE, "la_ds" }, \
+{ "4x", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = MFX_LOOKAHEAD_DS_4x }, INT_MIN, INT_MAX,                                            VE, "la_ds" }, \
 { "vcm",      "Use the video conferencing mode ratecontrol",  OFFSET(qsv.vcm),      AV_OPT_TYPE_INT, { .i64 = 0  },  0, 1,         VE },        \
 { "rdo",            "Enable rate distortion optimization",    OFFSET(qsv.rdo),            AV_OPT_TYPE_INT, { .i64 = -1 }, -1,          1, VE }, \
 { "max_frame_size", "Maximum encoded frame size in bytes",    OFFSET(qsv.max_frame_size), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, UINT16_MAX, VE }, \
@@ -116,6 +128,7 @@ typedef struct QSVEncContext {
     int avbr_accuracy;
     int avbr_convergence;
     int la_depth;
+    int la_ds;
     int vcm;
     int rdo;
     int max_frame_size;