diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 470bbc6017..e441486d9c 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -688,6 +688,8 @@ typedef struct AVIndexEntry {
  */
 #define AV_DISPOSITION_ATTACHED_PIC      0x0400
 
+typedef struct AVStreamInternal AVStreamInternal;
+
 /**
  * Stream structure.
  * New fields can be added to the end with minor version bumps.
@@ -878,6 +880,12 @@ typedef struct AVStream {
                                     support seeking natively. */
     int nb_index_entries;
     unsigned int index_entries_allocated_size;
+
+    /**
+     * An opaque field for libavformat internal usage.
+     * Must not be accessed in any way by callers.
+     */
+    AVStreamInternal *internal;
 } AVStream;
 
 #define AV_PROGRAM_RUNNING 1
diff --git a/libavformat/internal.h b/libavformat/internal.h
index a65a3b7f13..7bbf7755cf 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -90,6 +90,18 @@ struct AVFormatInternal {
      * Timebase for the timestamp offset.
      */
     AVRational offset_timebase;
+
+#if FF_API_COMPUTE_PKT_FIELDS2
+    int missing_ts_warning;
+#endif
+};
+
+struct AVStreamInternal {
+    /**
+     * Set to 1 if the codec allows reordering, so pts can be different
+     * from dts.
+     */
+    int reorder;
 };
 
 void ff_dynarray_add(intptr_t **tab_ptr, int *nb_ptr, intptr_t elem);
diff --git a/libavformat/mux.c b/libavformat/mux.c
index 4a81e36af5..7a51578f1c 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -92,6 +92,7 @@ static int init_muxer(AVFormatContext *s, AVDictionary **options)
     AVDictionary *tmp = NULL;
     AVCodecContext *codec = NULL;
     AVOutputFormat *of = s->oformat;
+    const AVCodecDescriptor *desc;
 
     if (options)
         av_dict_copy(&tmp, *options, 0);
@@ -171,6 +172,10 @@ FF_ENABLE_DEPRECATION_WARNINGS
             break;
         }
 
+        desc = avcodec_descriptor_get(codec->codec_id);
+        if (desc && desc->props & AV_CODEC_PROP_REORDER)
+            st->internal->reorder = 1;
+
         if (of->codec_tag) {
             if (codec->codec_tag &&
                 codec->codec_id == AV_CODEC_ID_RAWVIDEO &&
@@ -258,12 +263,23 @@ int avformat_write_header(AVFormatContext *s, AVDictionary **options)
     return 0;
 }
 
+#if FF_API_COMPUTE_PKT_FIELDS2
 //FIXME merge with compute_pkt_fields
 static int compute_pkt_fields2(AVFormatContext *s, AVStream *st, AVPacket *pkt)
 {
     int delay = FFMAX(st->codec->has_b_frames, !!st->codec->max_b_frames);
     int num, den, i;
 
+    if (!s->internal->missing_ts_warning &&
+        !(s->oformat->flags & AVFMT_NOTIMESTAMPS) &&
+        (pkt->pts == AV_NOPTS_VALUE || pkt->dts == AV_NOPTS_VALUE)) {
+        av_log(s, AV_LOG_WARNING,
+               "Timestamps are unset in a packet for stream %d. "
+               "This is deprecated and will stop working in the future. "
+               "Fix your code to set the timestamps properly\n", st->index);
+        s->internal->missing_ts_warning = 1;
+    }
+
     av_log(s, AV_LOG_TRACE, "compute_pkt_fields2: pts:%" PRId64 " dts:%" PRId64 " cur_dts:%" PRId64 " b:%d size:%d st:%d\n",
             pkt->pts, pkt->dts, st->cur_dts, delay, pkt->size, pkt->stream_index);
 
@@ -314,6 +330,7 @@ static int compute_pkt_fields2(AVFormatContext *s, AVStream *st, AVPacket *pkt)
 
     return 0;
 }
+#endif
 
 /*
  * FIXME: this function should NEVER get undefined pts/dts beside when the
@@ -381,7 +398,7 @@ static int check_packet(AVFormatContext *s, AVPacket *pkt)
     return 0;
 }
 
-int av_write_frame(AVFormatContext *s, AVPacket *pkt)
+static int prepare_input_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int ret;
 
@@ -389,16 +406,70 @@ int av_write_frame(AVFormatContext *s, AVPacket *pkt)
     if (ret < 0)
         return ret;
 
+#if !FF_API_COMPUTE_PKT_FIELDS2
+    /* sanitize the timestamps */
+    if (!(s->oformat->flags & AVFMT_NOTIMESTAMPS)) {
+        AVStream *st = s->streams[pkt->stream_index];
+
+        /* when there is no reordering (so dts is equal to pts), but
+         * only one of them is set, set the other as well */
+        if (!st->internal->reorder) {
+            if (pkt->pts == AV_NOPTS_VALUE && pkt->dts != AV_NOPTS_VALUE)
+                pkt->pts = pkt->dts;
+            if (pkt->dts == AV_NOPTS_VALUE && pkt->pts != AV_NOPTS_VALUE)
+                pkt->dts = pkt->pts;
+        }
+
+        /* check that the timestamps are set */
+        if (pkt->pts == AV_NOPTS_VALUE || pkt->dts == AV_NOPTS_VALUE) {
+            av_log(s, AV_LOG_ERROR,
+                   "Timestamps are unset in a packet for stream %d\n", st->index);
+            return AVERROR(EINVAL);
+        }
+
+        /* check that the dts are increasing (or at least non-decreasing,
+         * if the format allows it */
+        if (st->cur_dts != AV_NOPTS_VALUE &&
+            ((!(s->oformat->flags & AVFMT_TS_NONSTRICT) && st->cur_dts >= pkt->dts) ||
+             st->cur_dts > pkt->dts)) {
+            av_log(s, AV_LOG_ERROR,
+                   "Application provided invalid, non monotonically increasing "
+                   "dts to muxer in stream %d: %" PRId64 " >= %" PRId64 "\n",
+                   st->index, st->cur_dts, pkt->dts);
+            return AVERROR(EINVAL);
+        }
+
+        if (pkt->pts < pkt->dts) {
+            av_log(s, AV_LOG_ERROR, "pts %" PRId64 " < dts %" PRId64 " in stream %d\n",
+                   pkt->pts, pkt->dts, st->index);
+            return AVERROR(EINVAL);
+        }
+    }
+#endif
+
+    return 0;
+}
+
+int av_write_frame(AVFormatContext *s, AVPacket *pkt)
+{
+    int ret;
+
+    ret = prepare_input_packet(s, pkt);
+    if (ret < 0)
+        return ret;
+
     if (!pkt) {
         if (s->oformat->flags & AVFMT_ALLOW_FLUSH)
             return s->oformat->write_packet(s, pkt);
         return 1;
     }
 
+#if FF_API_COMPUTE_PKT_FIELDS2
     ret = compute_pkt_fields2(s, s->streams[pkt->stream_index], pkt);
 
     if (ret < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
         return ret;
+#endif
 
     ret = write_packet(s, pkt);
 
@@ -552,7 +623,7 @@ int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
 {
     int ret, flush = 0;
 
-    ret = check_packet(s, pkt);
+    ret = prepare_input_packet(s, pkt);
     if (ret < 0)
         goto fail;
 
@@ -561,8 +632,10 @@ int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
 
         av_log(s, AV_LOG_TRACE, "av_interleaved_write_frame size:%d dts:%" PRId64 " pts:%" PRId64 "\n",
                 pkt->size, pkt->dts, pkt->pts);
+#if FF_API_COMPUTE_PKT_FIELDS2
         if ((ret = compute_pkt_fields2(s, st, pkt)) < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
             goto fail;
+#endif
 
         if (pkt->dts == AV_NOPTS_VALUE && !(s->oformat->flags & AVFMT_NOTIMESTAMPS)) {
             ret = AVERROR(EINVAL);
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 734f83f1cd..bb17b4aedd 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2460,6 +2460,8 @@ static void free_stream(AVStream **pst)
     if (st->attached_pic.data)
         av_packet_unref(&st->attached_pic);
 
+    av_freep(&st->internal);
+
     av_dict_free(&st->metadata);
     av_freep(&st->probe_data.buf);
     av_free(st->index_entries);
@@ -2551,6 +2553,11 @@ AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
         av_free(st);
         return NULL;
     }
+
+    st->internal = av_mallocz(sizeof(*st->internal));
+    if (!st->internal)
+        goto fail;
+
     if (s->iformat) {
         /* no default bitrate if decoding */
         st->codec->bit_rate = 0;
@@ -2583,6 +2590,9 @@ AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
 
     s->streams[s->nb_streams++] = st;
     return st;
+fail:
+    free_stream(&st);
+    return NULL;
 }
 
 AVProgram *av_new_program(AVFormatContext *ac, int id)
diff --git a/libavformat/version.h b/libavformat/version.h
index d74968aa53..d004a55ad2 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -60,5 +60,8 @@
 #ifndef FF_API_LAVF_FMT_RAWPICTURE
 #define FF_API_LAVF_FMT_RAWPICTURE      (LIBAVFORMAT_VERSION_MAJOR < 58)
 #endif
+#ifndef FF_API_COMPUTE_PKT_FIELDS2
+#define FF_API_COMPUTE_PKT_FIELDS2      (LIBAVFORMAT_VERSION_MAJOR < 58)
+#endif
 
 #endif /* AVFORMAT_VERSION_H */