determine embedded block picture

src/vorbis_decoder/vorbis_decoder.cpp

@@ -15,7 +15,7 @@
  * adapted for the ESP32 by schreibfaul1
  *
  *  Created on: 13.02.2023
- *  Updated on: 13.12.2023
+ *  Updated on: 29.12.2023
  */
 //----------------------------------------------------------------------------------------------------------------------
 //                                     O G G    I M P L.
@@ -54,6 +54,9 @@ char     *s_vorbisChbuf = NULL;
 int32_t   s_vorbisValidSamples = 0;
 uint8_t   s_vorbisOldMode = 0;
 uint32_t  s_blocksizes[2];
+uint32_t  s_blockPicPos = 0;
+uint32_t  s_blockPicLen = 0;
+uint32_t  s_commentLength = 0;
 
 uint8_t   s_nrOfCodebooks = 0;
 uint8_t   s_nrOfFloors = 0;
@@ -152,6 +155,8 @@ void VORBISsetDefaults(){
     s_vorbisSegmentTableRdPtr = -1;
     s_vorbisError = 0;
     s_lastSegmentTableLen = 0;
+    s_blockPicPos = 0;
+    s_blockPicLen = 0;
 
     VORBISDecoder_ClearBuffers();
 }
@@ -190,17 +195,19 @@ int VORBISDecode(uint8_t *inbuf, int *bytesLeft, short *outbuf){
                     // log_i("first packet (identification len) %i", len);
                     s_identificatonHeaderLength = len;
                     ret = parseVorbisFirstPacket(inbuf, len);
+                    s_blockPicPos += 28;
                 }
             }
             else if(s_pageNr == 2){ // comment header
                 int idx = VORBIS_specialIndexOf(inbuf, "vorbis", 10);
+                s_blockPicPos += 6;
                 if(idx == 1){
                     // log_i("second packet (comment len) %i", len);
                     s_commentHeaderLength = len;
                     ret = parseVorbisComment(inbuf, len);
                 }
                 else{
-                    log_e("no \"vorbis\" something went wrong %i", len);
+                    ; // commentlength is greater than (one or more) OggS frame(s)
                 }
                 // log_w("s_vorbisSegmentTableSize %d", s_vorbisSegmentTableSize);
                 // Normally the segment table has two entries, the first for comments and the second for the codebooks
@@ -406,19 +413,21 @@ int parseVorbisFirstPacket(uint8_t *inbuf, int16_t nBytes){ // 4.2.2. Identifica
 int parseVorbisComment(uint8_t *inbuf, int16_t nBytes){      // reference https://xiph.org/vorbis/doc/v-comment.html
 
     // first bytes are: '.vorbis'
-    uint16_t pos = 7;
+    uint32_t pos = 7;
     uint32_t vendorLength       = *(inbuf + pos + 3) << 24; // lengt of vendor string, e.g. Xiph.Org libVorbis I 20070622
              vendorLength      += *(inbuf + pos + 2) << 16;
              vendorLength      += *(inbuf + pos + 1) << 8;
              vendorLength      += *(inbuf + pos);
 
     if(vendorLength > 254){  // guard
-       log_e("vorbis comment too long");
+       log_e("vorbis comment too long, vendorLength %i", vendorLength);
        return 0;
     }
+
     memcpy(s_vorbisChbuf, inbuf + 11, vendorLength);
     s_vorbisChbuf[vendorLength] = '\0';
     pos += 4 + vendorLength;
+    s_commentHeaderLength -= (7 + 4 + vendorLength);
 
     // log_i("vendorLength %x", vendorLength);
     // log_i("vendorString %s", s_vorbisChbuf);
@@ -426,6 +435,7 @@ int parseVorbisComment(uint8_t *inbuf, int16_t nBytes){      // reference https:
     uint8_t nrOfComments = *(inbuf + pos);
     // log_i("nrOfComments %i", nrOfComments);
     pos += 4;
+    s_commentHeaderLength -= 4;
 
     int idx = 0;
     char* artist = NULL;
@@ -437,23 +447,30 @@ int parseVorbisComment(uint8_t *inbuf, int16_t nBytes){      // reference https:
         commentLength += *(inbuf + pos + 2) << 16;
         commentLength += *(inbuf + pos + 1) << 8;
         commentLength += *(inbuf + pos);
+        s_commentLength = commentLength;
 
-        if(commentLength > 254) {log_i("vorbis comment too long"); return 0;}
-        memcpy(s_vorbisChbuf, inbuf + pos +  4, commentLength);
-        s_vorbisChbuf[commentLength] = '\0';
+        uint8_t cl = min((uint32_t)254, commentLength);
+        memcpy(s_vorbisChbuf, inbuf + pos +  4, cl);
+        s_vorbisChbuf[cl] = '\0';
 
         // log_i("commentLength %i comment %s", commentLength, s_vorbisChbuf);
-        pos += commentLength + 4;
 
         idx =        VORBIS_specialIndexOf((uint8_t*)s_vorbisChbuf, "artist=", 10);
         if(idx != 0) VORBIS_specialIndexOf((uint8_t*)s_vorbisChbuf, "ARTIST=", 10);
-        if(idx == 0){
-            artist = strndup((const char*)(s_vorbisChbuf + 7), commentLength - 7);
-        }
+        if(idx == 0){ artist = strndup((const char*)(s_vorbisChbuf + 7), commentLength - 7); s_commentLength = 0;}
+
         idx =        VORBIS_specialIndexOf((uint8_t*)s_vorbisChbuf, "title=", 10);
         if(idx != 0) VORBIS_specialIndexOf((uint8_t*)s_vorbisChbuf, "TITLE=", 10);
-        if(idx == 0){ title = strndup((const char*)(s_vorbisChbuf + 6), commentLength - 6);
-        }
+        if(idx == 0){ title = strndup((const char*)(s_vorbisChbuf + 6), commentLength - 6); s_commentLength = 0;}
+
+        idx =        VORBIS_specialIndexOf((uint8_t*)s_vorbisChbuf, "metadata_block_picture=", 25);
+        if(idx == 0){ s_blockPicLen = commentLength;
+                      s_blockPicPos += pos + 23;
+                      uint16_t blockPicLenUntilFrameEnd = s_commentHeaderLength - (4 + 23);
+                      log_w("metadata block picture found at pos %i, length %i, first blockLength %i", s_blockPicPos, s_blockPicLen, blockPicLenUntilFrameEnd);}
+
+        pos += commentLength + 4;
+        s_commentHeaderLength -= (4 + commentLength);
     }
     if(artist && title){
         strcpy(s_vorbisChbuf, artist);
@@ -587,6 +604,7 @@ int VORBISparseOGG(uint8_t *inbuf, int *bytesLeft){
         if(s_f_oggContinuedPage) return ERR_VORBIS_DECODER_ASYNC;
         inbuf += idx;
         *bytesLeft -= idx;
+        s_blockPicPos += idx;
     }
 
     int16_t segmentTableWrPtr = -1;
@@ -646,6 +664,7 @@ int VORBISparseOGG(uint8_t *inbuf, int *bytesLeft){
     }
 
     *bytesLeft -= headerSize;
+    s_blockPicPos += headerSize;
     if(s_pageNr < 4 && !continuedPage) s_pageNr++;
 
     s_f_oggFirstPage = firstPage;