[FFmpeg-cvslog] truehd_core: Use byte offsets instead of bit offsets
Andreas Rheinhardt
git at videolan.org
Tue Jul 9 14:59:57 EEST 2019
ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Sat Jul 6 16:18:03 2019 +0200| [836065b27a0f5b8268c2fb6c6e825ac3b63168f0] | committer: Paul B Mahol
truehd_core: Use byte offsets instead of bit offsets
Words of 16 bit are the unit for TrueHD's size and offset fields;
in particular the sizes of the high-level structures of TrueHD are
always a multiple of a byte; yet truehd_core unnecessarily used
bit offsets at several places. This has been changed.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=836065b27a0f5b8268c2fb6c6e825ac3b63168f0
---
libavcodec/truehd_core_bsf.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/libavcodec/truehd_core_bsf.c b/libavcodec/truehd_core_bsf.c
index 47684235db..8ea80d3015 100644
--- a/libavcodec/truehd_core_bsf.c
+++ b/libavcodec/truehd_core_bsf.c
@@ -45,7 +45,7 @@ static int truehd_core_filter(AVBSFContext *ctx, AVPacket *out)
int ret, i, last_offset = 0;
int in_size, out_size;
int have_header = 0;
- int substream_bits = 0;
+ int substream_bytes = 0;
int end;
ret = ff_bsf_get_packet(ctx, &in);
@@ -85,30 +85,32 @@ static int truehd_core_filter(AVBSFContext *ctx, AVPacket *out)
units[i].offset = get_bits(&gbc, 12);
if (i < 3) {
last_offset = units[i].offset * 2;
- substream_bits += 16;
+ substream_bytes += 2;
}
if (units[i].bits[0]) {
units[i].optional = get_bits(&gbc, 16);
if (i < 3)
- substream_bits += 16;
+ substream_bytes += 2;
}
}
- end = get_bits_count(&gbc);
+ end = get_bits_count(&gbc) >> 3;
- out_size = ((end + 7) >> 3) + 4 + last_offset;
+ out_size = end + 4 + last_offset;
if (out_size < in_size) {
- int bpos = 0, reduce = (end - have_header * 28 * 8 - substream_bits) >> 4;
+ int bpos = 0, reduce = end - have_header * 28 - substream_bytes;
uint16_t parity_nibble, dts = AV_RB16(in->data + 2);
uint16_t auheader;
+ av_assert1(reduce % 2 == 0);
+
ret = av_new_packet(out, out_size);
if (ret < 0)
goto fail;
AV_WB16(out->data + 2, dts);
parity_nibble = dts;
- out->size -= reduce * 2;
+ out->size -= reduce;
parity_nibble ^= out->size / 2;
if (have_header) {
@@ -146,8 +148,8 @@ static int truehd_core_filter(AVBSFContext *ctx, AVPacket *out)
parity_nibble &= 0xF;
memcpy(out->data + have_header * 28 + 4 + bpos,
- in->data + 4 + (end >> 3),
- out_size - (4 + (end >> 3)));
+ in->data + 4 + end,
+ out_size - (4 + end));
auheader = (parity_nibble ^ 0xF) << 12;
auheader |= (out->size / 2) & 0x0fff;
AV_WB16(out->data, auheader);
More information about the ffmpeg-cvslog
mailing list