Separate from part 2 for a clearer diff.
Now the true loop condition has been revealed: start < buf_end
Clarify loop by moving the detection of sequence_end_codes out of the loop.
See also commit fd93d5efe64206d5f1bce8c702602353444c0c1a regarding
sequence_end_codes
---
libavcodec/cbs_mpeg2.c | 31 ++++++++++++++++++-------------
1 file changed, 18 insertions(+), 13 deletions(-)
diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c
index bf95fb7546..53aa0ed3f6 100644
--- a/libavcodec/cbs_mpeg2.c
+++ b/libavcodec/cbs_mpeg2.c
@@ -149,7 +149,7 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
CodedBitstreamUnitType unit_type;
uint32_t start_code = -1;
size_t unit_size;
- int err, final = 0;
+ int err;
int i = -1; // offset for pre-increment
start = avpriv_find_start_code(start, buf_end, &start_code, 1);
@@ -161,16 +161,7 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
do {
unit_type = start_code & 0xff;
- 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
- // the next unit will be treated as the last unit.
- start_code = 0;
- }
- else {
- end = avpriv_find_start_code(start, buf_end, &start_code, 1);
- }
+ end = avpriv_find_start_code(start, buf_end, &start_code, 1);
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
@@ -182,8 +173,8 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
unit_size = (end - 4) - start;
} else {
// We didn't find a start code, so this is the final unit.
+ // There is no start code to remove from end, hence not (end - 4).
unit_size = end - start;
- final = 1;
}
err = ff_cbs_insert_unit_data(frag, ++i, unit_type,
@@ -193,7 +184,21 @@ static int cbs_mpeg2_split_fragment(CodedBitstreamContext
*ctx,
return err;
start = end;
- } while (!final);
+ } while (start < buf_end);
+
+ if (avpriv_start_code_is_valid(start_code)) {
+ // The last four bytes form a start code which constitutes
+ // a unit of its own, with size 1.
+
+ start--; // since start == buf_end because of the loop condition,
+ // decrement so start points to the byte containing the
start_code_identifier
+ err = ff_cbs_insert_unit_data(frag, ++i, start_code & 0xFF,
+ (uint8_t*)start /* cast away the const
to match parameter type */,
+ 1, frag->data_ref);
+ if (err < 0) {
+ return err;
+ }
+ }
return 0;
}
--
2.32.0
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