Allow remuxing of explicitly signalled AAC files into ADTS.

The ADTS output files are not explicitly signaled because the format
does not support explicit signalling.

Originally committed as revision 23935 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/adtsenc.c

@@ -23,6 +23,7 @@
 #include "libavcodec/get_bits.h"
 #include "libavcodec/put_bits.h"
 #include "libavcodec/avcodec.h"
+#include "libavcodec/mpeg4audio.h"
 #include "avformat.h"
 #include "adts.h"
 
@@ -30,11 +31,17 @@ int ff_adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf
 {
     GetBitContext gb;
     PutBitContext pb;
+    MPEG4AudioConfig m4ac;
+    int off;
 
     init_get_bits(&gb, buf, size * 8);
-    adts->objecttype = get_bits(&gb, 5) - 1;
-    adts->sample_rate_index = get_bits(&gb, 4);
-    adts->channel_conf = get_bits(&gb, 4);
+    off = ff_mpeg4audio_get_config(&m4ac, buf, size);
+    if (off < 0)
+        return off;
+    skip_bits_long(&gb, off);
+    adts->objecttype        = m4ac.object_type - 1;
+    adts->sample_rate_index = m4ac.sampling_index;
+    adts->channel_conf      = m4ac.chan_config;
 
     if (adts->objecttype > 3U) {
         av_log(s, AV_LOG_ERROR, "MPEG-4 AOT %d is not allowed in ADTS\n", adts->objecttype+1);
@@ -52,10 +59,6 @@ int ff_adts_decode_extradata(AVFormatContext *s, ADTSContext *adts, uint8_t *buf
         av_log(s, AV_LOG_ERROR, "Scalable configurations are not allowed in ADTS\n");
         return -1;
     }
-    if (get_bits(&gb, 1)) {
-        av_log_missing_feature(s, "Signaled SBR or PS", 0);
-        return -1;
-    }
     if (!adts->channel_conf) {
         init_put_bits(&pb, adts->pce_data, MAX_PCE_SIZE);