add new requirements to ogg mapping: vorbis comment block must come second after streaminfo; first packet must have a packet type byte of 0x7f; packet 0 version must be followed by a 2-byte count of the # of header packets

2025-12-16 18:54:26 +00:00 · 2004-09-10 00:38:21 +00:00
parent 10c6f0fef4
commit 69cfda7a20
16 changed files with 196 additions and 59 deletions
--- a/src/libFLAC/stream_encoder.c
+++ b/src/libFLAC/stream_encoder.c
@@ -880,6 +880,11 @@ FLAC_API FLAC__StreamEncoderState FLAC__stream_encoder_init(FLAC__StreamEncoder
 	 * Check to see if the supplied metadata contains a VORBIS_COMMENT;
 	 * if not, we will write an empty one (FLAC__add_metadata_block()
 	 * automatically supplies the vendor string).
+	 *
+	 * WATCHOUT: libOggFLAC depends on us to write this block after the
+	 * STREAMINFO since that's what the mapping requires.  (In the case
+	 * that metadata_has_vorbis_comment it true it will have already
+	 * insured that the metadata list is properly ordered.)
 	 */
 	if(!metadata_has_vorbis_comment) {
 		FLAC__StreamMetadata vorbis_comment;
--- a/src/libOggFLAC/include/private/ogg_encoder_aspect.h
+++ b/src/libOggFLAC/include/private/ogg_encoder_aspect.h
@@ -40,6 +40,7 @@
 typedef struct OggFLAC__OggEncoderAspect {
 	/* these are storage for values that can be set through the API */
 	long serial_number;
+	unsigned num_metadata;

 	/* these are for internal state related to Ogg encoding */
 	ogg_stream_state stream_state;
@@ -50,6 +51,7 @@ typedef struct OggFLAC__OggEncoderAspect {
 } OggFLAC__OggEncoderAspect;

 void OggFLAC__ogg_encoder_aspect_set_serial_number(OggFLAC__OggEncoderAspect *aspect, long value);
+FLAC__bool OggFLAC__ogg_encoder_aspect_set_num_metadata(OggFLAC__OggEncoderAspect *aspect, unsigned value);
 void OggFLAC__ogg_encoder_aspect_set_defaults(OggFLAC__OggEncoderAspect *aspect);
 FLAC__bool OggFLAC__ogg_encoder_aspect_init(OggFLAC__OggEncoderAspect *aspect);
 void OggFLAC__ogg_encoder_aspect_finish(OggFLAC__OggEncoderAspect *aspect);
--- a/src/libOggFLAC/include/private/ogg_mapping.h
+++ b/src/libOggFLAC/include/private/ogg_mapping.h
@@ -34,6 +34,13 @@

 #include "FLAC/ordinals.h"

+/** The length of the 'FLAC' magic in bytes. */
+#define OggFLAC__MAPPING_PACKET_TYPE_LENGTH (1u)
+
+extern const unsigned OggFLAC__MAPPING_PACKET_TYPE_LEN; /* = 8 bits */
+
+extern const FLAC__byte OggFLAC__MAPPING_FIRST_HEADER_PACKET_TYPE; /* = 0x7f */
+
 /** The length of the 'FLAC' magic in bytes. */
 #define OggFLAC__MAPPING_MAGIC_LENGTH (4u)

@@ -48,4 +55,9 @@ extern const unsigned OggFLAC__MAPPING_VERSION_MINOR_LEN; /* = 8 bits */
 /** The length of the Ogg FLAC mapping minor version number in bytes. */
 #define OggFLAC__MAPPING_VERSION_MINOR_LENGTH (1u)

+extern const unsigned OggFLAC__MAPPING_NUM_HEADERS_LEN; /* = 16 bits */
+
+/** The length of the #-of-header-packets number bytes. */
+#define OggFLAC__MAPPING_NUM_HEADERS_LENGTH (2u)
+
 #endif
--- a/src/libOggFLAC/ogg_decoder_aspect.c
+++ b/src/libOggFLAC/ogg_decoder_aspect.c
@@ -83,11 +83,6 @@ void OggFLAC__ogg_decoder_aspect_set_defaults(OggFLAC__OggDecoderAspect *aspect)
 }

 void OggFLAC__ogg_decoder_aspect_flush(OggFLAC__OggDecoderAspect *aspect)
-{
-	OggFLAC__ogg_decoder_aspect_reset(aspect);
-}
-
-void OggFLAC__ogg_decoder_aspect_reset(OggFLAC__OggDecoderAspect *aspect)
 {
 	(void)ogg_stream_reset(&aspect->stream_state);
 	(void)ogg_sync_reset(&aspect->sync_state);
@@ -95,6 +90,14 @@ void OggFLAC__ogg_decoder_aspect_reset(OggFLAC__OggDecoderAspect *aspect)
 	aspect->have_working_page = false;
 }

+void OggFLAC__ogg_decoder_aspect_reset(OggFLAC__OggDecoderAspect *aspect)
+{
+	OggFLAC__ogg_decoder_aspect_flush(aspect);
+
+	if(aspect->use_first_serial_number)
+		aspect->need_serial_number = true;
+}
+
 OggFLAC__OggDecoderAspectReadStatus OggFLAC__ogg_decoder_aspect_read_callback_wrapper(OggFLAC__OggDecoderAspect *aspect, FLAC__byte buffer[], unsigned *bytes, OggFLAC__OggDecoderAspectReadCallbackProxy read_callback, void *decoder, void *client_data)
 {
 	static const unsigned OGG_BYTES_CHUNK = 8192;
@@ -153,15 +156,24 @@ OggFLAC__OggDecoderAspectReadStatus OggFLAC__ogg_decoder_aspect_read_callback_wr
 				const int ret = ogg_stream_packetout(&aspect->stream_state, &aspect->working_packet);
 				if (ret > 0) {
 					aspect->have_working_packet = true;
-					/* if it is packet 0, check for magic and a supported Ogg FLAC mapping version */
-					if (aspect->working_packet.packetno == 0) {
-						const unsigned header_length = OggFLAC__MAPPING_MAGIC_LENGTH + OggFLAC__MAPPING_VERSION_MAJOR_LENGTH + OggFLAC__MAPPING_VERSION_MINOR_LENGTH;
+					/* if it is the first header packet, check for magic and a supported Ogg FLAC mapping version */
+					if (aspect->working_packet.bytes > 0 && aspect->working_packet.packet[0] == OggFLAC__MAPPING_FIRST_HEADER_PACKET_TYPE) {
+						const FLAC__byte *b = aspect->working_packet.packet;
+						const unsigned header_length =
+							OggFLAC__MAPPING_PACKET_TYPE_LENGTH +
+							OggFLAC__MAPPING_MAGIC_LENGTH +
+							OggFLAC__MAPPING_VERSION_MAJOR_LENGTH +
+							OggFLAC__MAPPING_VERSION_MINOR_LENGTH +
+							OggFLAC__MAPPING_NUM_HEADERS_LENGTH;
 						if (aspect->working_packet.bytes < (long)header_length)
 							return OggFLAC__OGG_DECODER_ASPECT_READ_STATUS_NOT_FLAC;
-						if (memcmp(aspect->working_packet.packet, OggFLAC__MAPPING_MAGIC, OggFLAC__MAPPING_MAGIC_LENGTH))
+						b += OggFLAC__MAPPING_PACKET_TYPE_LENGTH;
+						if (memcmp(b, OggFLAC__MAPPING_MAGIC, OggFLAC__MAPPING_MAGIC_LENGTH))
 							return OggFLAC__OGG_DECODER_ASPECT_READ_STATUS_NOT_FLAC;
-						aspect->version_major = (unsigned)aspect->working_packet.packet[OggFLAC__MAPPING_MAGIC_LENGTH];
-						aspect->version_minor = (unsigned)aspect->working_packet.packet[OggFLAC__MAPPING_MAGIC_LENGTH+OggFLAC__MAPPING_VERSION_MAJOR_LENGTH];
+						b += OggFLAC__MAPPING_MAGIC_LENGTH;
+						aspect->version_major = (unsigned)(*b);
+						b += OggFLAC__MAPPING_VERSION_MAJOR_LENGTH;
+						aspect->version_minor = (unsigned)(*b);
 						if (aspect->version_major != 1)
 							return OggFLAC__OGG_DECODER_ASPECT_READ_STATUS_UNSUPPORTED_MAPPING_VERSION;
 						aspect->working_packet.packet += header_length;
--- a/src/libOggFLAC/ogg_encoder_aspect.c
+++ b/src/libOggFLAC/ogg_encoder_aspect.c
@@ -67,17 +67,31 @@ void OggFLAC__ogg_encoder_aspect_set_serial_number(OggFLAC__OggEncoderAspect *as
 	aspect->serial_number = value;
 }

+FLAC__bool OggFLAC__ogg_encoder_aspect_set_num_metadata(OggFLAC__OggEncoderAspect *aspect, unsigned value)
+{
+	if(value < (1u << OggFLAC__MAPPING_NUM_HEADERS_LEN)) {
+		aspect->num_metadata = value;
+		return true;
+	}
+	else
+		return false;
+}
+
 void OggFLAC__ogg_encoder_aspect_set_defaults(OggFLAC__OggEncoderAspect *aspect)
 {
 	aspect->serial_number = 0;
+	aspect->num_metadata = 0;
 }

 /*
 * The basic FLAC -> Ogg mapping goes like this:
 *
 * - 'fLaC' magic and STREAMINFO block get combined into the first
- *   packet.  The packet is prefixed with 'FLAC' magic and the 2
- *   byte Ogg FLAC mapping version number.
+ *   packet.  The packet is prefixed with
+ *   + the one-byte packet type 0x7F
+ *   + 'FLAC' magic
+ *   + the 2 byte Ogg FLAC mapping version number
+ *   + tne 2 byte big-endian # of header packets
 * - The first packet is flushed to the first page.
 * - Each subsequent metadata block goes into its own packet.
 * - Each metadata packet is flushed to page (this is not required,
@@ -110,9 +124,11 @@ FLAC__StreamEncoderWriteStatus OggFLAC__ogg_encoder_aspect_write_callback_wrappe

 		if(aspect->is_first_packet) {
 			FLAC__byte newbuffer[
+				OggFLAC__MAPPING_PACKET_TYPE_LENGTH +
 				OggFLAC__MAPPING_MAGIC_LENGTH +
 				OggFLAC__MAPPING_VERSION_MAJOR_LENGTH +
 				OggFLAC__MAPPING_VERSION_MINOR_LENGTH +
+				OggFLAC__MAPPING_NUM_HEADERS_LENGTH +
 				FLAC__STREAM_SYNC_LENGTH +
 				FLAC__STREAM_METADATA_HEADER_LENGTH +
 				FLAC__STREAM_METADATA_STREAMINFO_LENGTH
@@ -126,6 +142,9 @@ FLAC__StreamEncoderWriteStatus OggFLAC__ogg_encoder_aspect_write_callback_wrappe
 				FLAC__ASSERT(0);
 				return FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR;
 			}
+			/* add first header packet type */
+			*b = OggFLAC__MAPPING_FIRST_HEADER_PACKET_TYPE;
+			b += OggFLAC__MAPPING_PACKET_TYPE_LENGTH;
 			/* add 'FLAC' mapping magic */
 			memcpy(b, OggFLAC__MAPPING_MAGIC, OggFLAC__MAPPING_MAGIC_LENGTH);
 			b += OggFLAC__MAPPING_MAGIC_LENGTH;
@@ -135,6 +154,11 @@ FLAC__StreamEncoderWriteStatus OggFLAC__ogg_encoder_aspect_write_callback_wrappe
 			/* add Ogg FLAC mapping minor version number */
 			memcpy(b, &OggFLAC__MAPPING_VERSION_MINOR, OggFLAC__MAPPING_VERSION_MINOR_LENGTH);
 			b += OggFLAC__MAPPING_VERSION_MINOR_LENGTH;
+			/* add number of header packets */
+			*b = (FLAC__byte)(aspect->num_metadata >> 8);
+			b++;
+			*b = (FLAC__byte)(aspect->num_metadata);
+			b++;
 			/* add native FLAC 'fLaC' magic */
 			memcpy(b, FLAC__STREAM_SYNC_STRING, FLAC__STREAM_SYNC_LENGTH);
 			b += FLAC__STREAM_SYNC_LENGTH;
@@ -158,7 +182,7 @@ FLAC__StreamEncoderWriteStatus OggFLAC__ogg_encoder_aspect_write_callback_wrappe
 		if(ogg_stream_packetin(&aspect->stream_state, &packet) != 0)
 			return FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR;

-		/*@@@@@@ can't figure out a way to pass a useful number for 'samples' to the write_callback, so we'll just pass 0 */
+		/*@@@ can't figure out a way to pass a useful number for 'samples' to the write_callback, so we'll just pass 0 */
 		if(is_metadata) {
 			while(ogg_stream_flush(&aspect->stream_state, &aspect->page) != 0) {
 				if(write_callback(encoder, aspect->page.header, aspect->page.header_len, 0, current_frame, client_data) != FLAC__STREAM_ENCODER_WRITE_STATUS_OK)
--- a/src/libOggFLAC/ogg_mapping.c
+++ b/src/libOggFLAC/ogg_mapping.c
@@ -31,7 +31,13 @@

 #include "private/ogg_mapping.h"

+const unsigned OggFLAC__MAPPING_PACKET_TYPE_LEN = 8; /* bits */
+
+const FLAC__byte OggFLAC__MAPPING_FIRST_HEADER_PACKET_TYPE = 0x7f;
+
 const FLAC__byte * const OggFLAC__MAPPING_MAGIC = "FLAC";

 const unsigned OggFLAC__MAPPING_VERSION_MAJOR_LEN = 8; /* bits */
 const unsigned OggFLAC__MAPPING_VERSION_MINOR_LEN = 8; /* bits */
+
+const unsigned OggFLAC__MAPPING_NUM_HEADERS_LEN = 16; /* bits */
--- a/src/libOggFLAC/seekable_stream_encoder.c
+++ b/src/libOggFLAC/seekable_stream_encoder.c
@@ -442,15 +442,31 @@ OggFLAC_API FLAC__bool OggFLAC__seekable_stream_encoder_set_metadata(OggFLAC__Se
 	FLAC__ASSERT(0 != encoder->private_->FLAC_stream_encoder);
 	if(encoder->protected_->state != OggFLAC__SEEKABLE_STREAM_ENCODER_UNINITIALIZED)
 		return false;
+	/* reorder metadata if necessary to ensure that any VORBIS_COMMENT is the first, according to the mapping spec */
+	if(0 != metadata && num_blocks > 1) {
+		unsigned i;
+		for(i = 1; i < num_blocks; i++) {
+			if(0 != metadata[i] && metadata[i]->type == FLAC__METADATA_TYPE_VORBIS_COMMENT) {
+				FLAC__StreamMetadata *vc = metadata[i];
+				for( ; i > 0; i--)
+					metadata[i] = metadata[i-1];
+				metadata[0] = vc;
+				break;
+			}
+		}
+	}
 	if(0 != metadata && num_blocks > 0) {
 		unsigned i;
 		for(i = 0; i < num_blocks; i++) {
+			/* keep track of any SEEKTABLE block */
 			if(0 != metadata[i] && metadata[i]->type == FLAC__METADATA_TYPE_SEEKTABLE) {
 				encoder->private_->seek_table = &metadata[i]->data.seek_table;
 				break; /* take only the first one */
 			}
 		}
 	}
+	if(!OggFLAC__ogg_encoder_aspect_set_num_metadata(&encoder->protected_->ogg_encoder_aspect, num_blocks))
+		return false;
 	return FLAC__stream_encoder_set_metadata(encoder->private_->FLAC_stream_encoder, metadata, num_blocks);
 }

--- a/src/libOggFLAC/stream_encoder.c
+++ b/src/libOggFLAC/stream_encoder.c
@@ -397,6 +397,21 @@ OggFLAC_API FLAC__bool OggFLAC__stream_encoder_set_metadata(OggFLAC__StreamEncod
 	FLAC__ASSERT(0 != encoder->private_->FLAC_stream_encoder);
 	if(encoder->protected_->state != OggFLAC__STREAM_ENCODER_UNINITIALIZED)
 		return false;
+	/* reorder metadata if necessary to ensure that any VORBIS_COMMENT is the first, according to the mapping spec */
+	if(0 != metadata && num_blocks > 1) {
+		unsigned i;
+		for(i = 1; i < num_blocks; i++) {
+			if(0 != metadata[i] && metadata[i]->type == FLAC__METADATA_TYPE_VORBIS_COMMENT) {
+				FLAC__StreamMetadata *vc = metadata[i];
+				for( ; i > 0; i--)
+					metadata[i] = metadata[i-1];
+				metadata[0] = vc;
+				break;
+			}
+		}
+	}
+	if(!OggFLAC__ogg_encoder_aspect_set_num_metadata(&encoder->protected_->ogg_encoder_aspect, num_blocks))
+		return false;
 	return FLAC__stream_encoder_set_metadata(encoder->private_->FLAC_stream_encoder, metadata, num_blocks);
 }

--- a/src/test_libOggFLAC++/decoders.cpp
+++ b/src/test_libOggFLAC++/decoders.cpp
@@ -69,6 +69,7 @@ static bool generate_file_()
 	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;
+	/* WATCHOUT: the encoder should move the VORBIS_COMMENT block to the front, right after STREAMINFO */

 	if(!file_utils__generate_oggflacfile(oggflacfilename_, &oggflacfilesize_, 512 * 1024, &streaminfo_, expected_metadata_sequence_, num_expected_))
 		return die_("creating the encoded file");
@@ -454,11 +455,11 @@ static bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -531,9 +532,9 @@ static bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -560,10 +561,10 @@ static bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -597,9 +598,9 @@ static bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -738,10 +739,10 @@ static bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -782,11 +783,11 @@ static bool test_stream_decoder()
 	/* done, now leave the sequence the way we found it... */
 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1189,11 +1190,11 @@ static bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1266,9 +1267,9 @@ static bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1295,10 +1296,10 @@ static bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1332,9 +1333,9 @@ static bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1473,10 +1474,10 @@ static bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1517,11 +1518,11 @@ static bool test_seekable_stream_decoder()
 	/* done, now leave the sequence the way we found it... */
 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1834,11 +1835,11 @@ static bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1911,9 +1912,9 @@ static bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1940,10 +1941,10 @@ static bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1977,9 +1978,9 @@ static bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -2118,10 +2119,10 @@ static bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -2162,11 +2163,11 @@ static bool test_file_decoder()
 	/* done, now leave the sequence the way we found it... */
 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

--- a/src/test_libOggFLAC++/encoders.cpp
+++ b/src/test_libOggFLAC++/encoders.cpp
@@ -28,7 +28,7 @@ extern "C" {
 #include <string.h>

 static ::FLAC__StreamMetadata streaminfo_, padding_, seektable_, application1_, application2_, vorbiscomment_, cuesheet_, unknown_;
-static ::FLAC__StreamMetadata *metadata_sequence_[] = { &padding_, &seektable_, &application1_, &application2_, &vorbiscomment_, &cuesheet_, &unknown_ };
+static ::FLAC__StreamMetadata *metadata_sequence_[] = { &vorbiscomment_, &padding_, &seektable_, &application1_, &application2_, &cuesheet_, &unknown_ };
 static const unsigned num_metadata_ = sizeof(metadata_sequence_) / sizeof(metadata_sequence_[0]);
 static const char *oggflacfilename_ = "metadata.ogg";

--- a/src/test_libOggFLAC/decoders.c
+++ b/src/test_libOggFLAC/decoders.c
@@ -139,6 +139,7 @@ static FLAC__bool generate_file_()
 	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;
+	/* WATCHOUT: the encoder should move the VORBIS_COMMENT block to the front, right after STREAMINFO */

 	if(!file_utils__generate_oggflacfile(oggflacfilename_, &oggflacfilesize_, 512 * 1024, &streaminfo_, expected_metadata_sequence_, num_expected_))
 		return die_("creating the encoded file");
@@ -504,11 +505,11 @@ static FLAC__bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -571,9 +572,9 @@ static FLAC__bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -596,10 +597,10 @@ static FLAC__bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -627,9 +628,9 @@ static FLAC__bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -744,10 +745,10 @@ static FLAC__bool test_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -782,11 +783,11 @@ static FLAC__bool test_stream_decoder()
 	/* done, now leave the sequence the way we found it... */
 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1223,11 +1224,11 @@ static FLAC__bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1290,9 +1291,9 @@ static FLAC__bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1315,10 +1316,10 @@ static FLAC__bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1346,9 +1347,9 @@ static FLAC__bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1463,10 +1464,10 @@ static FLAC__bool test_seekable_stream_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1501,11 +1502,11 @@ static FLAC__bool test_seekable_stream_decoder()
 	/* done, now leave the sequence the way we found it... */
 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1773,11 +1774,11 @@ static FLAC__bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1840,9 +1841,9 @@ static FLAC__bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1865,10 +1866,10 @@ static FLAC__bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -1896,9 +1897,9 @@ static FLAC__bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -2013,10 +2014,10 @@ static FLAC__bool test_file_decoder()

 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

@@ -2051,11 +2052,11 @@ static FLAC__bool test_file_decoder()
 	/* done, now leave the sequence the way we found it... */
 	num_expected_ = 0;
 	expected_metadata_sequence_[num_expected_++] = &streaminfo_;
+	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &padding_;
 	expected_metadata_sequence_[num_expected_++] = &seektable_;
 	expected_metadata_sequence_[num_expected_++] = &application1_;
 	expected_metadata_sequence_[num_expected_++] = &application2_;
-	expected_metadata_sequence_[num_expected_++] = &vorbiscomment_;
 	expected_metadata_sequence_[num_expected_++] = &cuesheet_;
 	expected_metadata_sequence_[num_expected_++] = &unknown_;

--- a/src/test_libOggFLAC/encoders.c
+++ b/src/test_libOggFLAC/encoders.c
@@ -29,7 +29,7 @@
 #include <string.h>

 static FLAC__StreamMetadata streaminfo_, padding_, seektable_, application1_, application2_, vorbiscomment_, cuesheet_, unknown_;
-static FLAC__StreamMetadata *metadata_sequence_[] = { &padding_, &seektable_, &application1_, &application2_, &vorbiscomment_, &cuesheet_, &unknown_ };
+static FLAC__StreamMetadata *metadata_sequence_[] = { &vorbiscomment_, &padding_, &seektable_, &application1_, &application2_, &cuesheet_, &unknown_ };
 static const unsigned num_metadata_ = sizeof(metadata_sequence_) / sizeof(metadata_sequence_[0]);
 static const char *oggflacfilename_ = "metadata.ogg";