avcodec/libvpxenc: enable dynamic max quantizer reconfiguration

Signed-off-by: James Zern <jzern@google.com>

doc/encoders.texi

@@ -1996,8 +1996,11 @@ kilobits/s.
 @item keyint_min (@emph{kf-min-dist})
 
 @item qmin (@emph{min-q})
+Minimum (Best Quality) Quantizer.
 
 @item qmax (@emph{max-q})
+Maximum (Worst Quality) Quantizer.
+Can be changed per-frame.
 
 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are

libavcodec/libvpxenc.c

@@ -1629,6 +1629,16 @@ static int vpx_encode(AVCodecContext *avctx, AVPacket *pkt,
     vpx_svc_layer_id_t layer_id;
     int layer_id_valid = 0;
 
+    if (avctx->qmax >= 0 && enccfg->rc_max_quantizer != avctx->qmax) {
+        struct vpx_codec_enc_cfg cfg = *enccfg;
+        cfg.rc_max_quantizer = avctx->qmax;
+        res = vpx_codec_enc_config_set(&ctx->encoder, &cfg);
+        if (res != VPX_CODEC_OK) {
+            log_encoder_error(avctx, "Error reconfiguring encoder");
+            return AVERROR_INVALIDDATA;
+        }
+    }
+
     if (frame) {
         const AVFrameSideData *sd = av_frame_get_side_data(frame, AV_FRAME_DATA_REGIONS_OF_INTEREST);
         rawimg                      = &ctx->rawimg;

libavcodec/version.h

@@ -30,7 +30,7 @@
 #include "version_major.h"
 
 #define LIBAVCODEC_VERSION_MINOR  25
-#define LIBAVCODEC_VERSION_MICRO 100
+#define LIBAVCODEC_VERSION_MICRO 101
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \