Support "VLB " audio in NSV files.

See samples/nsv/vlb_audio.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

libavcodec/aac.h

@@ -300,6 +300,7 @@ typedef struct {
     DECLARE_ALIGNED(32, float, temp)[128];
 
     enum OCStatus output_configured;
+    int warned_num_aac_frames;
 } AACContext;
 
 #endif /* AVCODEC_AAC_H */

libavcodec/aacdec.c

@@ -2125,13 +2125,14 @@ static int parse_adts_frame_header(AACContext *ac, GetBitContext *gb)
         }
         if (!ac->avctx->sample_rate)
             ac->avctx->sample_rate = hdr_info.sample_rate;
-        if (hdr_info.num_aac_frames == 1) {
-            if (!hdr_info.crc_absent)
-                skip_bits(gb, 16);
-        } else {
+        if (!ac->warned_num_aac_frames && hdr_info.num_aac_frames != 1) {
+            // This is 2 for "VLB " audio in NSV files.
+            // See samples/nsv/vlb_audio.
             av_log_missing_feature(ac->avctx, "More than one AAC RDB per ADTS frame is", 0);
-            return -1;
+            ac->warned_num_aac_frames = 1;
         }
+        if (!hdr_info.crc_absent)
+            skip_bits(gb, 16);
     }
     return size;
 }

libavformat/nsvdec.c

@@ -206,6 +206,7 @@ static const AVCodecTag nsv_codec_audio_tags[] = {
     { CODEC_ID_MP3,       MKTAG('M', 'P', '3', ' ') },
     { CODEC_ID_AAC,       MKTAG('A', 'A', 'C', ' ') },
     { CODEC_ID_AAC,       MKTAG('A', 'A', 'C', 'P') },
+    { CODEC_ID_AAC,       MKTAG('V', 'L', 'B', ' ') },
     { CODEC_ID_SPEEX,     MKTAG('S', 'P', 'X', ' ') },
     { CODEC_ID_PCM_U16LE, MKTAG('P', 'C', 'M', ' ') },
     { CODEC_ID_NONE,      0 },