Set default qmax for VC-3/DNxHD to 1024 (maximum allowed by VC-3 spec).

Also increase the global limit on qmax.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/dnxhdenc.c

@@ -32,6 +32,7 @@
 #include "mpegvideo.h"
 #include "mpegvideo_common.h"
 #include "dnxhdenc.h"
+#include "internal.h"
 
 #define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
 #define DNX10BIT_QMAT_SHIFT 18 // The largest value that will not lead to overflow for 10bit samples.
@@ -990,6 +991,11 @@ static int dnxhd_encode_end(AVCodecContext *avctx)
     return 0;
 }
 
+static const AVCodecDefault dnxhd_defaults[] = {
+    { "qmax", "1024" }, /* Maximum quantization scale factor allowed for VC-3 */
+    { NULL },
+};
+
 AVCodec ff_dnxhd_encoder = {
     .name           = "dnxhd",
     .type           = AVMEDIA_TYPE_VIDEO,
@@ -1002,4 +1008,5 @@ AVCodec ff_dnxhd_encoder = {
     .pix_fmts = (const enum PixelFormat[]){PIX_FMT_YUV422P, PIX_FMT_YUV422P10, PIX_FMT_NONE},
     .long_name = NULL_IF_CONFIG_SMALL("VC3/DNxHD"),
     .priv_class = &class,
+    .defaults       = dnxhd_defaults,
 };

libavcodec/options.c

@@ -133,7 +133,7 @@ static const AVOption options[]={
 {"qcomp", "video quantizer scale compression (VBR)", OFFSET(qcompress), AV_OPT_TYPE_FLOAT, {.dbl = 0.5 }, -FLT_MAX, FLT_MAX, V|E},
 {"qblur", "video quantizer scale blur (VBR)", OFFSET(qblur), AV_OPT_TYPE_FLOAT, {.dbl = 0.5 }, -1, FLT_MAX, V|E},
 {"qmin", "min video quantizer scale (VBR)", OFFSET(qmin), AV_OPT_TYPE_INT, {.dbl = 2 }, -1, 69, V|E},
-{"qmax", "max video quantizer scale (VBR)", OFFSET(qmax), AV_OPT_TYPE_INT, {.dbl = 31 }, -1, 69, V|E},
+{"qmax", "max video quantizer scale (VBR)", OFFSET(qmax), AV_OPT_TYPE_INT, {.dbl = 31 }, -1, 1024, V|E},
 {"qdiff", "max difference between the quantizer scale (VBR)", OFFSET(max_qdiff), AV_OPT_TYPE_INT, {.dbl = 3 }, INT_MIN, INT_MAX, V|E},
 {"bf", "use 'frames' B frames", OFFSET(max_b_frames), AV_OPT_TYPE_INT, {.dbl = DEFAULT }, -1, FF_MAX_B_FRAMES, V|E},
 {"b_qfactor", "qp factor between p and b frames", OFFSET(b_quant_factor), AV_OPT_TYPE_FLOAT, {.dbl = 1.25 }, -FLT_MAX, FLT_MAX, V|E},