diff --git a/libavcodec/h264_mp4toannexb_bsf.c b/libavcodec/h264_mp4toannexb_bsf.c
index 292d106433..794c82e650 100644
--- a/libavcodec/h264_mp4toannexb_bsf.c
+++ b/libavcodec/h264_mp4toannexb_bsf.c
@@ -26,6 +26,7 @@
 
 #include "avcodec.h"
 #include "bsf.h"
+#include "h264.h"
 
 typedef struct H264BSFContext {
     int32_t  sps_offset;
@@ -209,9 +210,9 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
         if (nal_size > buf_end - buf || nal_size < 0)
             goto fail;
 
-        if (unit_type == 7)
+        if (unit_type == H264_NAL_SPS)
             s->idr_sps_seen = s->new_idr = 1;
-        else if (unit_type == 8) {
+        else if (unit_type == H264_NAL_PPS) {
             s->idr_pps_seen = s->new_idr = 1;
             /* if SPS has not been seen yet, prepend the AVCC one to PPS */
             if (!s->idr_sps_seen) {
@@ -232,18 +233,18 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
         /* if this is a new IDR picture following an IDR picture, reset the idr flag.
          * Just check first_mb_in_slice to be 0 as this is the simplest solution.
          * This could be checking idr_pic_id instead, but would complexify the parsing. */
-        if (!s->new_idr && unit_type == 5 && (buf[1] & 0x80))
+        if (!s->new_idr && unit_type == H264_NAL_IDR_SLICE && (buf[1] & 0x80))
             s->new_idr = 1;
 
         /* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */
-        if (s->new_idr && unit_type == 5 && !s->idr_sps_seen && !s->idr_pps_seen) {
+        if (s->new_idr && unit_type == H264_NAL_IDR_SLICE && !s->idr_sps_seen && !s->idr_pps_seen) {
             if ((ret=alloc_and_copy(out,
                                ctx->par_out->extradata, ctx->par_out->extradata_size,
                                buf, nal_size, 1)) < 0)
                 goto fail;
             s->new_idr = 0;
         /* if only SPS has been seen, also insert PPS */
-        } else if (s->new_idr && unit_type == 5 && s->idr_sps_seen && !s->idr_pps_seen) {
+        } else if (s->new_idr && unit_type == H264_NAL_IDR_SLICE && s->idr_sps_seen && !s->idr_pps_seen) {
             if (s->pps_offset == -1) {
                 av_log(ctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
                 if ((ret = alloc_and_copy(out, NULL, 0, buf, nal_size, 0)) < 0)
@@ -253,9 +254,9 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
                                         buf, nal_size, 1)) < 0)
                 goto fail;
         } else {
-            if ((ret=alloc_and_copy(out, NULL, 0, buf, nal_size, unit_type == 7 || unit_type == 8)) < 0)
+            if ((ret=alloc_and_copy(out, NULL, 0, buf, nal_size, unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS)) < 0)
                 goto fail;
-            if (!s->new_idr && unit_type == 1) {
+            if (!s->new_idr && unit_type == H264_NAL_SLICE) {
                 s->new_idr = 1;
                 s->idr_sps_seen = 0;
                 s->idr_pps_seen = 0;