ff_cbs_insert_unit_data() does not modify the data or data_size fields of
the CodedBitstreamFragment. It also does not modify the value pointed to
by start. (We don't need that byte in this function anymore, anyway.)
---
libavcodec/cbs_mpeg2.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c
index afe78eef9a..f2efedde5d 100644
--- a/libavcodec/cbs_mpeg2.c
+++ b/libavcodec/cbs_mpeg2.c
@@ -144,23 +144,24 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
CodedBitstreamFragment *frag,
int header)
{
- const uint8_t *start, *end;
+ const uint8_t *start = frag->data, *end;
+ const uint8_t * const buf_end = frag->data + frag->data_size;
CodedBitstreamUnitType unit_type;
uint32_t start_code = -1;
size_t unit_size;
- int err, i = 0, final = 0;
+ int err, final = 0;
+ int i = -1; // offset for pre-increment
- start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
- &start_code, 1);
+ start = avpriv_find_start_code(start, buf_end, &start_code, 1);
if (!avpriv_start_code_is_valid(start_code)) {
// No start code found.
return AVERROR_INVALIDDATA;
}
- while (!final) {
+ do {
unit_type = start_code & 0xff;
- if (start == frag->data + frag->data_size) {
+ if (start == buf_end) {
// The last four bytes form a start code which constitutes
// a unit of its own. In this situation avpriv_find_start_code
// won't modify start_code at all so modify start_code so that
@@ -168,10 +169,9 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
start_code = 0;
}
- end = avpriv_find_start_code(start--, frag->data + frag->data_size,
- &start_code, 0);
-
- // start points to the byte containing the start_code_identifier
+ end = avpriv_find_start_code(start, buf_end, &start_code, 0);
+ start--;
+ // decrement so start points to the byte containing the
start_code_identifier
// (may be the last byte of fragment->data); end points to the byte
// following the byte containing the start code identifier (or to
// the end of fragment->data).
@@ -185,14 +185,14 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
final = 1;
}
- err = ff_cbs_insert_unit_data(frag, i, unit_type, (uint8_t*)start,
+ err = ff_cbs_insert_unit_data(frag, ++i, unit_type,
+ (uint8_t*)start /* cast away the const
to match parameter type */,
unit_size, frag->data_ref);
if (err < 0)
return err;
start = end;
- i++;
- }
+ } while (!final);
return 0;
}
--
2.32.0
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
