diff --git a/libavcodec/libspeexenc.c b/libavcodec/libspeexenc.c
index 32abadcef1..6e1591b397 100644
--- a/libavcodec/libspeexenc.c
+++ b/libavcodec/libspeexenc.c
@@ -292,7 +292,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
         s->pkt_frame_count = 0;
         if ((ret = ff_alloc_packet(avctx, avpkt, speex_bits_nbytes(&s->bits))) < 0)
             return ret;
-        ret = speex_bits_write(&s->bits, avpkt->data, avpkt->size);
+        avpkt->size = speex_bits_write(&s->bits, avpkt->data, avpkt->size);
         speex_bits_reset(&s->bits);
 
         /* Get the next frame pts/duration */
@@ -301,7 +301,6 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
         if (ret < 0)
             return ret;
 
-        avpkt->size = ret;
         *got_packet_ptr = 1;
         return 0;
     }
diff --git a/tests/fate/enc_external.mak b/tests/fate/enc_external.mak
index 705f733db7..ec6ae83373 100644
--- a/tests/fate/enc_external.mak
+++ b/tests/fate/enc_external.mak
@@ -14,3 +14,18 @@ fate-libx264-hdr10: CMD = enc_external $(TARGET_SAMPLES)/hevc/hdr10_plus_h265_sa
 
 FATE_SAMPLES_FFMPEG_FFPROBE += $(FATE_ENC_EXTERNAL-yes)
 fate-enc-external: $(FATE_ENC_EXTERNAL-yes)
+
+# Check decoded frame counts without depending on libspeex's encoded bytes.
+FATE_LIBSPEEX-$(call ALLYES, LIBSPEEX_ENCODER SPEEX_DECODER OGG_MUXER OGG_DEMUXER LAVFI_INDEV SINE_FILTER ARESAMPLE_FILTER \
+                               PCM_S16$(if $(filter yes,$(HAVE_BIGENDIAN)),BE,LE)_DECODER FILE_PROTOCOL) += fate-libspeex-encode fate-libspeex-encode-stereo
+fate-libspeex-encode: SPEEX_OPTS = -ac 1
+fate-libspeex-encode-stereo: SPEEX_OPTS = -ac 2 -frames_per_packet 2
+$(FATE_LIBSPEEX-yes): CMD = run_with_temp \
+    "$(FFMPEG) -nostdin -hide_banner -loglevel error \
+    -f lavfi -i sine=frequency=1000:sample_rate=32000:duration=1 \
+    -c:a libspeex -b:a 30k $(SPEEX_OPTS) -f ogg -y" \
+    "ffprobe$(PROGSSUF)$(EXESUF) -v error -bitexact -count_frames \
+    -show_entries stream=codec_name,sample_rate,channels,nb_read_frames" ogg
+
+FATE_FFMPEG_FFPROBE += $(FATE_LIBSPEEX-yes)
+fate-enc-external: $(FATE_LIBSPEEX-yes)
diff --git a/tests/ref/fate/libspeex-encode b/tests/ref/fate/libspeex-encode
new file mode 100644
index 0000000000..179ea07d71
--- /dev/null
+++ b/tests/ref/fate/libspeex-encode
@@ -0,0 +1,6 @@
+[STREAM]
+codec_name=speex
+sample_rate=32000
+channels=1
+nb_read_frames=50
+[/STREAM]
diff --git a/tests/ref/fate/libspeex-encode-stereo b/tests/ref/fate/libspeex-encode-stereo
new file mode 100644
index 0000000000..ea01697eb4
--- /dev/null
+++ b/tests/ref/fate/libspeex-encode-stereo
@@ -0,0 +1,6 @@
+[STREAM]
+codec_name=speex
+sample_rate=32000
+channels=2
+nb_read_frames=25
+[/STREAM]