am ed46ba26: am 41e8e4a2: am 804878f3: Merge "Skip any number of leading ID3v2... (5833ae3c) · Commits · e / os / android_frameworks_base

media/libstagefright/MP3Extractor.cpp

+31 −51

Original line number	Diff line number	Diff line
		@@ -311,15 +311,19 @@ static bool Resync(
		// Skip an optional ID3 header if syncing at the very beginning
		// of the datasource.

		for (;;) {
		uint8_t id3header[10];
		if (source->readAt(0, id3header, sizeof(id3header))
		if (source->readAt(*inout_pos, id3header, sizeof(id3header))
		< (ssize_t)sizeof(id3header)) {
		// If we can't even read these 10 bytes, we might as well bail out,
		// even if there _were_ 10 bytes of valid mp3 audio data...
		// If we can't even read these 10 bytes, we might as well bail
		// out, even if there _were_ 10 bytes of valid mp3 audio data...
		return false;
		}

		if (id3header[0] == 'I' && id3header[1] == 'D' && id3header[2] == '3') {
		if (memcmp("ID3", id3header, 3)) {
		break;
		}

		// Skip the ID3v2 header.

		size_t len =
		@@ -331,50 +335,30 @@ static bool Resync(
		len += 10;

		*inout_pos += len;

		LOGV("skipped ID3 tag, new starting offset is %ld (0x%08lx)",
		inout_pos, inout_pos);
		}
		}

		const size_t kMaxFrameSize = 4096;
		uint8_t *buffer = new uint8_t[kMaxFrameSize];

		off_t pos = *inout_pos - kMaxFrameSize;
		size_t buffer_offset = kMaxFrameSize;
		size_t buffer_length = kMaxFrameSize;
		off_t pos = *inout_pos;
		bool valid = false;
		do {
		if (buffer_offset + 3 >= buffer_length) {
		if (buffer_length < kMaxFrameSize) {
		break;
		}

		pos += buffer_offset;

		if (pos >= inout_pos + 128 1024) {
		// Don't scan forever.
		LOGV("giving up at offset %ld", pos);
		break;
		}

		memmove(buffer, &buffer[buffer_offset], buffer_length - buffer_offset);
		buffer_length = buffer_length - buffer_offset;
		buffer_offset = 0;

		ssize_t n = source->readAt(
		pos, &buffer[buffer_length], kMaxFrameSize - buffer_length);

		if (n <= 0) {
		uint8_t tmp[4];
		if (source->readAt(pos, tmp, 4) != 4) {
		break;
		}

		buffer_length += (size_t)n;

		continue;
		}

		uint32_t header = U32_AT(&buffer[buffer_offset]);
		uint32_t header = U32_AT(tmp);

		if (match_header != 0 && (header & kMask) != (match_header & kMask)) {
		++buffer_offset;
		++pos;
		continue;
		}

		@@ -382,16 +366,16 @@ static bool Resync(
		int sample_rate, num_channels, bitrate;
		if (!get_mp3_frame_size(header, &frame_size,
		&sample_rate, &num_channels, &bitrate)) {
		++buffer_offset;
		++pos;
		continue;
		}

		LOGV("found possible 1st frame at %ld", pos + buffer_offset);
		LOGV("found possible 1st frame at %ld (header = 0x%08x)", pos, header);

		// We found what looks like a valid frame,
		// now find its successors.

		off_t test_pos = pos + buffer_offset + frame_size;
		off_t test_pos = pos + frame_size;

		valid = true;
		for (int j = 0; j < 3; ++j) {
		@@ -422,7 +406,7 @@ static bool Resync(
		}

		if (valid) {
		*inout_pos = pos + buffer_offset;
		*inout_pos = pos;

		if (out_header != NULL) {
		*out_header = header;
		@@ -431,13 +415,9 @@ static bool Resync(
		LOGV("no dice, no valid sequence of frames found.");
		}

		++buffer_offset;

		++pos;
		} while (!valid);

		delete[] buffer;
		buffer = NULL;

		return valid;
		}