diff --git a/libavcodec/aacenc.c b/libavcodec/aacenc.c
index 553a5ae42d..1de266de62 100644
--- a/libavcodec/aacenc.c
+++ b/libavcodec/aacenc.c
@@ -908,40 +908,50 @@ static av_cold int aac_encode_init(AVCodecContext *avctx)
     uint8_t grouping[AAC_MAX_CHANNELS];
     int lengths[2];
 
-    s->channels = avctx->channels;
-    s->chan_map = aac_chan_configs[s->channels-1];
-    s->lambda = avctx->global_quality > 0 ? avctx->global_quality : 120;
+    /* Constants */
     s->last_frame_pb_count = 0;
     avctx->extradata_size = 5;
     avctx->frame_size = 1024;
     avctx->initial_padding = 1024;
-    avctx->bit_rate = (int)FFMIN(
-        6144 * s->channels / 1024.0 * avctx->sample_rate,
-        avctx->bit_rate);
-    avctx->profile = avctx->profile == FF_PROFILE_UNKNOWN ? FF_PROFILE_AAC_LOW :
-                     avctx->profile;
+    s->lambda = avctx->global_quality > 0 ? avctx->global_quality : 120;
 
+    /* Channel map and unspecified bitrate guessing */
+    s->channels = avctx->channels;
+    ERROR_IF(s->channels > AAC_MAX_CHANNELS || s->channels == 7,
+             "Unsupported number of channels: %d\n", s->channels);
+    s->chan_map = aac_chan_configs[s->channels-1];
+    if (!avctx->bit_rate) {
+        for (i = 1; i <= s->chan_map[0]; i++) {
+            avctx->bit_rate += s->chan_map[i] == TYPE_CPE ? 128000 : /* Pair */
+                               s->chan_map[i] == TYPE_LFE ? 16000  : /* LFE  */
+                                                            69000  ; /* SCE  */
+        }
+    }
+
+    /* Samplerate */
     for (i = 0; i < 16; i++)
         if (avctx->sample_rate == avpriv_mpeg4audio_sample_rates[i])
             break;
     s->samplerate_index = i;
-
     ERROR_IF(s->samplerate_index == 16 ||
              s->samplerate_index >= ff_aac_swb_size_1024_len ||
              s->samplerate_index >= ff_aac_swb_size_128_len,
              "Unsupported sample rate %d\n", avctx->sample_rate);
-    ERROR_IF(s->channels > AAC_MAX_CHANNELS || s->channels == 7,
-             "Unsupported number of channels: %d\n", s->channels);
+
+    /* Bitrate limiting */
     WARN_IF(1024.0 * avctx->bit_rate / avctx->sample_rate > 6144 * s->channels,
              "Too many bits %f > %d per frame requested, clamping to max\n",
              1024.0 * avctx->bit_rate / avctx->sample_rate,
              6144 * s->channels);
+    avctx->bit_rate = (int64_t)FFMIN(6144 * s->channels / 1024.0 * avctx->sample_rate,
+                                     avctx->bit_rate);
 
+    /* Profile and option setting */
+    avctx->profile = avctx->profile == FF_PROFILE_UNKNOWN ? FF_PROFILE_AAC_LOW :
+                     avctx->profile;
     for (i = 0; i < FF_ARRAY_ELEMS(aacenc_profiles); i++)
         if (avctx->profile == aacenc_profiles[i])
             break;
-    ERROR_IF(i == FF_ARRAY_ELEMS(aacenc_profiles),
-             "Unsupported encoding profile: %d\n", avctx->profile);
     if (avctx->profile == FF_PROFILE_MPEG2_AAC_LOW) {
         avctx->profile = FF_PROFILE_AAC_LOW;
         ERROR_IF(s->options.pred,
@@ -973,15 +983,15 @@ static av_cold int aac_encode_init(AVCodecContext *avctx)
                  "LTP prediction unavailable in the \"aac_main\" profile\n");
     }
     s->profile = avctx->profile;
-    s->coder = &ff_aac_coders[s->options.coder];
 
+    /* Coder limitations */
+    s->coder = &ff_aac_coders[s->options.coder];
     if (s->options.coder != AAC_CODER_TWOLOOP) {
         ERROR_IF(avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL,
                  "Coders other than twoloop require -strict -2 and some may be removed in the future\n");
         s->options.intensity_stereo = 0;
         s->options.pns = 0;
     }
-
     ERROR_IF(s->options.ltp && avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL,
              "The LPT profile requires experimental compliance, add -strict -2 to enable!\n");
 
@@ -1042,6 +1052,11 @@ static const AVClass aacenc_class = {
     LIBAVUTIL_VERSION_INT,
 };
 
+static const AVCodecDefault aac_encode_defaults[] = {
+    { "b", "0" },
+    { NULL }
+};
+
 AVCodec ff_aac_encoder = {
     .name           = "aac",
     .long_name      = NULL_IF_CONFIG_SMALL("AAC (Advanced Audio Coding)"),
@@ -1051,6 +1066,7 @@ AVCodec ff_aac_encoder = {
     .init           = aac_encode_init,
     .encode2        = aac_encode_frame,
     .close          = aac_encode_end,
+    .defaults       = aac_encode_defaults,
     .supported_samplerates = mpeg4audio_sample_rates,
     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
     .capabilities   = AV_CODEC_CAP_SMALL_LAST_FRAME | AV_CODEC_CAP_DELAY,