mp3 header bitstream syntax:
header()
{
syncword 12bits bslsf
id 1bit bslsf
layer 2bit bslsf
protection_bit 1bit bslsf
bitrate_index 4bits bslsf
sampling_frequency 2bits bslsf
padding_bit 1bit bslsf
private_bit 1bit bslsf
mode 2bits bslsf
mode_extension 2bits bslsf
copyright 1bit bslsf
original/home 1bit bslsf
emphasis 2bits bslsf
}
if the header is masking with MP3_MASK(0xFFFE0CCF), below fields will be cleared:
protection_bit, bitrate_index, sampling_freqency, mode
with SAME_HEADER_MASK(0xFFFE0C00), extra below fields will be cleared which didn't make
sense:
mode_extension, copyright, original/home, emphasis
As the MP3_MASK is good for same mp3 header masking and is defined in the
header, so it's preferable to remove SAME_HEADER_MASK to keep the masking same.
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
#define XING_TOC_COUNT 100
-#define SAME_HEADER_MASK \
- (0xffe00000 | (3 << 17) | (3 << 10) | (3 << 19))
typedef struct {
AVClass *class;
ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
ret = check(s->pb, off + i + frame_size, &header2);
if (ret >= 0 &&
- (header & SAME_HEADER_MASK) == (header2 & SAME_HEADER_MASK))
+ (header & MP3_MASK) == (header2 & MP3_MASK))
{
av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
ret = avio_seek(s->pb, off + i, SEEK_SET);