diff --git a/libavformat/4xm.c b/libavformat/4xm.c
index 7db3e602a5..2caa08f4c7 100644
--- a/libavformat/4xm.c
+++ b/libavformat/4xm.c
@@ -47,6 +47,7 @@
 #define  MOVI_TAG FOURCC_TAG('M', 'O', 'V', 'I')
 #define  VTRK_TAG FOURCC_TAG('V', 'T', 'R', 'K')
 #define  STRK_TAG FOURCC_TAG('S', 'T', 'R', 'K')
+#define  std__TAG FOURCC_TAG('s', 't', 'd', '_')
 #define  name_TAG FOURCC_TAG('n', 'a', 'm', 'e')
 #define  vtrk_TAG FOURCC_TAG('v', 't', 'r', 'k')
 #define  strk_TAG FOURCC_TAG('s', 't', 'r', 'k')
@@ -82,11 +83,31 @@ typedef struct FourxmDemuxContext {
     AudioTrack *tracks;
     int selected_track;
 
-    int64_t pts;
-    int last_chunk_was_audio;
-    int last_audio_frame_count;
+    int64_t audio_pts;
+    int64_t video_pts;
+    int video_pts_inc;
 } FourxmDemuxContext;
 
+static float get_le_float(unsigned char *buffer)
+{
+    float f;
+    unsigned char *float_buffer = (unsigned char *)&f;
+
+#ifdef WORDS_BIGENDIAN
+    float_buffer[0] = buffer[3];
+    float_buffer[1] = buffer[2];
+    float_buffer[2] = buffer[1];
+    float_buffer[3] = buffer[0];
+#else
+    float_buffer[0] = buffer[0];
+    float_buffer[1] = buffer[1];
+    float_buffer[2] = buffer[2];
+    float_buffer[3] = buffer[3];
+#endif
+
+    return f;
+}
+
 static int fourxm_probe(AVProbeData *p)
 {
     if (p->buf_size < 12)
@@ -111,6 +132,7 @@ static int fourxm_read_header(AVFormatContext *s,
     int i;
     int current_track = -1;
     AVStream *st;
+    float fps;
 
     fourxm->track_count = 0;
     fourxm->tracks = NULL;
@@ -137,7 +159,10 @@ static int fourxm_read_header(AVFormatContext *s,
         fourcc_tag = LE_32(&header[i]);
         size = LE_32(&header[i + 4]);
 
-        if (fourcc_tag == vtrk_TAG) {
+        if (fourcc_tag == std__TAG) {
+            fps = get_le_float(&header[i + 12]);
+            fourxm->video_pts_inc = (int)(90000.0 / fps);
+        } else if (fourcc_tag == vtrk_TAG) {
             /* check that there is enough data */
             if (size != vtrk_SIZE) {
                 av_free(header);
@@ -180,7 +205,6 @@ static int fourxm_read_header(AVFormatContext *s,
             fourxm->tracks[current_track].channels = LE_32(&header[i + 36]);
             fourxm->tracks[current_track].sample_rate = LE_32(&header[i + 40]);
             fourxm->tracks[current_track].bits = LE_32(&header[i + 44]);
-            printf("bps:%d\n", fourxm->tracks[current_track].bits);
             i += 8 + size;
 
             /* allocate a new AVStream */
@@ -215,9 +239,8 @@ static int fourxm_read_header(AVFormatContext *s,
         return AVERROR_INVALIDDATA;
 
     /* initialize context members */
-    fourxm->pts = 0;
-    fourxm->last_chunk_was_audio = 0;
-    fourxm->last_audio_frame_count = 0;
+    fourxm->video_pts = -fourxm->video_pts_inc;  /* first frame will push to 0 */
+    fourxm->audio_pts = 0;
 
     /* set the pts reference (1 pts = 1/90000) */
     s->pts_num = 1;
@@ -238,6 +261,7 @@ static int fourxm_read_packet(AVFormatContext *s,
     int packet_read = 0;
     unsigned char header[8];
     int64_t pts_inc;
+    int audio_frame_count;
 
     while (!packet_read) {
 
@@ -250,6 +274,9 @@ static int fourxm_read_packet(AVFormatContext *s,
         switch (fourcc_tag) {
 
         case LIST_TAG:
+            /* this is a good time to bump the video pts */
+            fourxm->video_pts += fourxm->video_pts_inc;
+
             /* skip the LIST-* tag and move on to the next fourcc */
             get_le32(pb);
             break;
@@ -258,21 +285,12 @@ static int fourxm_read_packet(AVFormatContext *s,
         case pfrm_TAG:
         case cfrm_TAG:{
 
-            /* bump the pts if the last data sent out was audio */
-            if (fourxm->last_chunk_was_audio) {
-                fourxm->last_chunk_was_audio = 0;
-                pts_inc = fourxm->last_audio_frame_count;
-                pts_inc *= 90000;
-                pts_inc /= fourxm->tracks[fourxm->selected_track].sample_rate;
-                fourxm->pts += pts_inc;
-            }
-
             /* allocate 8 more bytes than 'size' to account for fourcc
              * and size */
             if (av_new_packet(pkt, size + 8))
                 return -EIO;
             pkt->stream_index = fourxm->video_stream_index;
-            pkt->pts = fourxm->pts;
+            pkt->pts = fourxm->video_pts;
             memcpy(pkt->data, header, 8);
             ret = get_buffer(&s->pb, &pkt->data[8], size);
 
@@ -293,18 +311,29 @@ static int fourxm_read_packet(AVFormatContext *s,
                     return -EIO;
                 pkt->stream_index = 
                     fourxm->tracks[fourxm->selected_track].stream_index;
-                pkt->pts = fourxm->pts;
+                pkt->pts = fourxm->audio_pts;
                 ret = get_buffer(&s->pb, pkt->data, size);
                 if (ret < 0)
                     av_free_packet(pkt);
                 else
                     packet_read = 1;
 
-                /* maintain pts info for the benefit of the video track */
-                fourxm->last_chunk_was_audio = 1;
-                fourxm->last_audio_frame_count = size /
-                    ((fourxm->tracks[fourxm->selected_track].bits / 8) *
-                      fourxm->tracks[fourxm->selected_track].channels);
+                /* pts accounting */
+                audio_frame_count = size;
+                if (fourxm->tracks[fourxm->selected_track].adpcm)
+                    audio_frame_count -= 
+                        2 * (fourxm->tracks[fourxm->selected_track].channels);
+                audio_frame_count /=
+                      fourxm->tracks[fourxm->selected_track].channels;
+                if (fourxm->tracks[fourxm->selected_track].adpcm)
+                    audio_frame_count *= 2;
+                else 
+                    audio_frame_count /=
+                    (fourxm->tracks[fourxm->selected_track].bits / 8);
+                pts_inc = audio_frame_count;
+                pts_inc *= 90000;
+                pts_inc /= fourxm->tracks[fourxm->selected_track].sample_rate;
+                fourxm->audio_pts += pts_inc;
 
             } else {
                 url_fseek(pb, size, SEEK_CUR);