avcodec/nvenc: zero avg and max bitrate in CQ mode

Signed-off-by: Timo Rothenpieler <timo@rothenpieler.org>

libavcodec/nvenc.c

@@ -947,12 +947,17 @@ static av_cold void nvenc_setup_rate_control(AVCodecContext *avctx)
     if (ctx->zerolatency)
         ctx->encode_config.rcParams.zeroReorderDelay = 1;
 
-    if (ctx->quality)
-    {
+    if (ctx->quality) {
         //convert from float to fixed point 8.8
         int tmp_quality = (int)(ctx->quality * 256.0f);
         ctx->encode_config.rcParams.targetQuality = (uint8_t)(tmp_quality >> 8);
         ctx->encode_config.rcParams.targetQualityLSB = (uint8_t)(tmp_quality & 0xff);
+
+        av_log(avctx, AV_LOG_VERBOSE, "CQ(%d) mode enabled.\n", tmp_quality);
+
+        //CQ mode shall discard max & avg bitrate;
+        avctx->bit_rate    = ctx->encode_config.rcParams.averageBitRate = 0;
+        avctx->rc_max_rate = ctx->encode_config.rcParams.maxBitRate     = 0;
     }
 }