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Merge "Skip any number of leading ID3v2 tags (instead of just the first), also simplify/fix the find-consecutive-mp3-frames functionality." into froyo

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This commit is contained in:
Andreas Huber
2010-03-31 11:33:19 -07:00
committed by Android (Google) Code Review
parent e259bc770b 0d34d8b4d5
commit 804878f3a3
1 changed files with 32 additions and 52 deletions
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84
media/libstagefright/MP3Extractor.cpp
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@@ -311,15 +311,19 @@ static bool Resync(
// Skip an optional ID3 header if syncing at the very beginning // Skip an optional ID3 header if syncing at the very beginning
// of the datasource. // of the datasource.
uint8_t id3header[10]; for (;;) {
if (source->readAt(0, id3header, sizeof(id3header)) uint8_t id3header[10];
< (ssize_t)sizeof(id3header)) { if (source->readAt(*inout_pos, id3header, sizeof(id3header))
// If we can't even read these 10 bytes, we might as well bail out, < (ssize_t)sizeof(id3header)) {
// 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
return false; // out, even if there _were_ 10 bytes of valid mp3 audio data...
} return false;
}
if (memcmp("ID3", id3header, 3)) {
break;
}
if (id3header[0] == 'I' && id3header[1] == 'D' && id3header[2] == '3') {
// Skip the ID3v2 header. // Skip the ID3v2 header.
size_t len = size_t len =
@@ -331,50 +335,30 @@ static bool Resync(
len += 10; len += 10;
*inout_pos += len; *inout_pos += len;
LOGV("skipped ID3 tag, new starting offset is %ld (0x%08lx)",
*inout_pos, *inout_pos);
} }
} }
const size_t kMaxFrameSize = 4096; off_t pos = *inout_pos;
uint8_t *buffer = new uint8_t[kMaxFrameSize];
off_t pos = *inout_pos - kMaxFrameSize;
size_t buffer_offset = kMaxFrameSize;
size_t buffer_length = kMaxFrameSize;
bool valid = false; bool valid = false;
do { do {
if (buffer_offset + 3 >= buffer_length) { if (pos >= *inout_pos + 128 * 1024) {
if (buffer_length < kMaxFrameSize) { // Don't scan forever.
break; LOGV("giving up at offset %ld", pos);
} 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) {
break;
}
buffer_length += (size_t)n;
continue;
} }
uint32_t header = U32_AT(&buffer[buffer_offset]); uint8_t tmp[4];
if (source->readAt(pos, tmp, 4) != 4) {
break;
}
uint32_t header = U32_AT(tmp);
if (match_header != 0 && (header & kMask) != (match_header & kMask)) { if (match_header != 0 && (header & kMask) != (match_header & kMask)) {
++buffer_offset; ++pos;
continue; continue;
} }
@@ -382,16 +366,16 @@ static bool Resync(
int sample_rate, num_channels, bitrate; int sample_rate, num_channels, bitrate;
if (!get_mp3_frame_size(header, &frame_size, if (!get_mp3_frame_size(header, &frame_size,
&sample_rate, &num_channels, &bitrate)) { &sample_rate, &num_channels, &bitrate)) {
++buffer_offset; ++pos;
continue; 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, // We found what looks like a valid frame,
// now find its successors. // now find its successors.
off_t test_pos = pos + buffer_offset + frame_size; off_t test_pos = pos + frame_size;
valid = true; valid = true;
for (int j = 0; j < 3; ++j) { for (int j = 0; j < 3; ++j) {
@@ -422,7 +406,7 @@ static bool Resync(
} }
if (valid) { if (valid) {
*inout_pos = pos + buffer_offset; *inout_pos = pos;
if (out_header != NULL) { if (out_header != NULL) {
*out_header = header; *out_header = header;
@@ -431,13 +415,9 @@ static bool Resync(
LOGV("no dice, no valid sequence of frames found."); LOGV("no dice, no valid sequence of frames found.");
} }
++buffer_offset; ++pos;
} while (!valid); } while (!valid);
delete[] buffer;
buffer = NULL;
return valid; return valid;
} }