diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index e94d16b513..45c9dd1959 100644
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -312,6 +312,33 @@ static inline short adpcm_ima_expand_nibble(ADPCMChannelStatus *c, char nibble)
     return (short)predictor;
 }
 
+static inline short adpcm_4xa_expand_nibble(ADPCMChannelStatus *c, char nibble)
+{
+    int step_index;
+    int predictor;
+    int sign, delta, diff, step;
+
+    step = step_table[c->step_index];
+    step_index = c->step_index + index_table[(unsigned)nibble];
+    if (step_index < 0) step_index = 0;
+    else if (step_index > 88) step_index = 88;
+
+    sign = nibble & 8;
+    delta = nibble & 7;
+    
+    diff = (delta*step + (step>>1))>>3; // difference to code above
+    
+    predictor = c->predictor;
+    if (sign) predictor -= diff;
+    else predictor += diff;
+
+    CLAMP_TO_SHORT(predictor);
+    c->predictor = predictor;
+    c->step_index = step_index;
+
+    return (short)predictor;
+}
+
 static inline short adpcm_ms_expand_nibble(ADPCMChannelStatus *c, char nibble)
 {
     int predictor;
@@ -334,7 +361,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
 {
     ADPCMContext *c = avctx->priv_data;
     ADPCMChannelStatus *cs;
-    int n, m, channel;
+    int n, m, channel, i;
     int block_predictor[2];
     short *samples;
     uint8_t *src;
@@ -444,6 +471,34 @@ static int adpcm_decode_frame(AVCodecContext *avctx,
 	    }
 	    src++;
 	}
+        break;
+    case CODEC_ID_ADPCM_4XM:
+        cs = &(c->status[0]);
+        c->status[0].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2;
+        if(st){
+            c->status[1].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2;
+        }
+        c->status[0].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2;
+        if(st){
+            c->status[1].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2;
+        }
+//            if (cs->step_index < 0) cs->step_index = 0;
+//            if (cs->step_index > 88) cs->step_index = 88;
+
+        m= (buf_size - (src - buf))>>st;
+//printf("%d %d %d %d\n", st, m, c->status[0].predictor, c->status[0].step_index);
+        //FIXME / XXX decode chanels individual & interleave samples
+        for(i=0; i<m; i++) {
+	    *samples++ = adpcm_4xa_expand_nibble(&c->status[0], src[i] & 0x0F);
+            if (st)
+                *samples++ = adpcm_4xa_expand_nibble(&c->status[1], src[i+m] & 0x0F);
+            *samples++ = adpcm_4xa_expand_nibble(&c->status[0], src[i] >> 4);
+	    if (st)
+                *samples++ = adpcm_4xa_expand_nibble(&c->status[1], src[i+m] >> 4);
+	}
+
+        src += m<<st;
+
         break;
     case CODEC_ID_ADPCM_MS:
 
@@ -529,6 +584,7 @@ AVCodec name ## _decoder = {                    \
 ADPCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);
 ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
 ADPCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
+ADPCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);
 
 #undef ADPCM_CODEC
 
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 980a470a84..15b78b53c0 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -133,6 +133,7 @@ PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
 PCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);
 PCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
 PCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
+PCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);
 
 #undef PCM_CODEC
 }
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 7ed71c5c7f..195dff586d 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1269,6 +1269,7 @@ PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
 PCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);
 PCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
 PCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
+PCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);
 
 #undef PCM_CODEC
 
diff --git a/libavformat/4xm.c b/libavformat/4xm.c
index 9e924da7a1..39ac06d7e5 100644
--- a/libavformat/4xm.c
+++ b/libavformat/4xm.c
@@ -71,6 +71,7 @@ typedef struct AudioTrack {
     int bits;
     int channels;
     int stream_index;
+    int adpcm;
 } AudioTrack;
 
 typedef struct FourxmDemuxContext {
@@ -172,9 +173,11 @@ static int fourxm_read_header(AVFormatContext *s,
                     return AVERROR_NOMEM;
                 }
             }
+            fourxm->tracks[current_track].adpcm = LE_32(&header[i + 12]);
             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 */
@@ -192,7 +195,9 @@ static int fourxm_read_header(AVFormatContext *s,
             st->codec.bit_rate = st->codec.channels * st->codec.sample_rate *
                 st->codec.bits_per_sample;
             st->codec.block_align = st->codec.channels * st->codec.bits_per_sample;
-            if (st->codec.bits_per_sample == 8)
+            if (fourxm->tracks[current_track].adpcm)
+                st->codec.codec_id = CODEC_ID_ADPCM_4XM;
+            else if (st->codec.bits_per_sample == 8)
                 st->codec.codec_id = CODEC_ID_PCM_U8;
             else
                 st->codec.codec_id = CODEC_ID_PCM_S16LE;
@@ -224,7 +229,7 @@ static int fourxm_read_packet(AVFormatContext *s,
     FourxmDemuxContext *fourxm = s->priv_data;
     ByteIOContext *pb = &s->pb;
     unsigned int fourcc_tag;
-    unsigned int size;
+    unsigned int size, out_size;
     int ret = 0;
     int track_number;
     int packet_read = 0;
@@ -237,10 +242,9 @@ static int fourxm_read_packet(AVFormatContext *s,
             return ret;
         fourcc_tag = LE_32(&header[0]);
         size = LE_32(&header[4]);
-
+//printf(" %8X %c%c%c%c %d\n", fourcc_tag, fourcc_tag, fourcc_tag>>8, fourcc_tag>>16, fourcc_tag>>24, size);
         if (url_feof(pb))
             return -EIO;
-
         switch (fourcc_tag) {
 
         case LIST_TAG:
@@ -277,7 +281,7 @@ if (fourcc_tag == cfrm_TAG) {
 id = LE_32(&pkt->data[12]);
 whole = LE_32(&pkt->data[16]);
 stats[id] += size - 12;
-printf(" cfrm chunk id:%d size:%d whole:%d until now:%d\n", id, size, whole, stats[id]);
+//printf(" cfrm chunk id:%d size:%d whole:%d until now:%d\n", id, size, whole, stats[id]);
 }
 
             if (ret < 0)
@@ -290,7 +294,9 @@ printf(" cfrm chunk id:%d size:%d whole:%d until now:%d\n", id, size, whole, sta
         case snd__TAG:
 printf (" snd_ chunk, ");
             track_number = get_le32(pb);
-            size = get_le32(pb);
+            out_size= get_le32(pb);
+            size-=8;
+
             if (track_number == fourxm->selected_track) {
 printf ("correct track, dispatching...\n");
                 if (av_new_packet(pkt, size))
@@ -321,7 +327,6 @@ printf ("wrong track, skipping...\n");
             break;
         }
     }
-
     return ret;
 }