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find AAC frames

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Find AAC frames in the input and skip invalid data.  This prepares AAC
streaming.
This commit is contained in:
Max Kellermann 2008-08-26 08:27:11 +02:00
parent f43e39047d
commit 00c47b3c85
1 changed files with 35 additions and 1 deletions
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36
src/inputPlugins/aac_plugin.c
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@ -111,6 +111,40 @@ static size_t adts_check_frame(AacBuffer * b)
(b->buffer[5] >> 5);
}
/**
* Find the next AAC frame in the buffer. Returns 0 if no frame is
* found or if not enough data is available.
*/
static size_t adts_find_frame(AacBuffer * b)
{
const unsigned char *p;
size_t frame_length;
while ((p = memchr(b->buffer, 0xff, b->bytesIntoBuffer)) != NULL) {
/* discard data before 0xff */
if (p > b->buffer)
aac_buffer_shift(b, p - b->buffer);
if (b->bytesIntoBuffer <= 7)
/* not enough data yet */
return 0;
/* is it a frame? */
frame_length = adts_check_frame(b);
if (frame_length > 0)
/* yes, it is */
return frame_length;
/* it's just some random 0xff byte; discard and and
continue searching */
aac_buffer_shift(b, 1);
}
/* nothing at all; discard the whole buffer */
aac_buffer_shift(b, b->bytesIntoBuffer);
return 0;
}
static void adtsParse(AacBuffer * b, float *length)
{
unsigned int frames, frameLength;
@ -121,7 +155,7 @@ static void adtsParse(AacBuffer * b, float *length)
for (frames = 0;; frames++) {
fillAacBuffer(b);
frameLength = adts_check_frame(b);
frameLength = adts_find_frame(b);
if (frameLength > 0) {
if (frames == 0) {
sampleRate = adtsSampleRates[(b->