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mkvmuxer: fix DiscardPadding

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DiscardPadding is a signed int.
this change fixes 2 things:
- allows negative values for discard padding
- fixes cases where an unsigned value would be written such that on read
  the sign would be flipped

Change-Id: I9418da7a22c09768e02d5b61da8d01c2bccb5dee
This commit is contained in:
James Zern 2014-06-16 12:31:38 -07:00
parent 8be63972fd
commit 574045edd4
2 changed files with 24 additions and 8 deletions
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10
mkvmuxer.cpp
View File

@ -1636,7 +1636,7 @@ bool Cluster::DoWriteBlockWithDiscardPadding(
const uint8* frame, uint64 length, int64 discard_padding,
uint64 track_number, uint64 abs_timecode, uint64 generic_arg,
WriteBlockDiscardPadding write_block) {
if (frame == NULL || length == 0 || discard_padding <= 0)
if (frame == NULL || length == 0)
return false;
if (!IsValidTrackNumber(track_number))
@ -2430,7 +2430,7 @@ bool Segment::AddFrameWithDiscardPadding(const uint8* frame, uint64 length,
int64 discard_padding,
uint64 track_number, uint64 timestamp,
bool is_key) {
if (frame == NULL || discard_padding <= 0)
if (frame == NULL)
return false;
if (!CheckHeaderInfo())
@ -2547,7 +2547,7 @@ bool Segment::AddGenericFrame(const Frame* frame) {
frame->frame(), frame->length(), frame->additional(),
frame->additional_length(), frame->add_id(), frame->track_number(),
frame->timestamp(), frame->is_key());
} else if (frame->discard_padding() > 0) {
} else if (frame->discard_padding() != 0) {
return AddFrameWithDiscardPadding(
frame->frame(), frame->length(), frame->discard_padding(),
frame->track_number(), frame->timestamp(), frame->is_key());
@ -3025,7 +3025,7 @@ int Segment::WriteFramesAll() {
const uint64 frame_timestamp = frame->timestamp(); // ns
const uint64 frame_timecode = frame_timestamp / timecode_scale;
if (frame->discard_padding() > 0) {
if (frame->discard_padding() != 0) {
if (!cluster->AddFrameWithDiscardPadding(
frame->frame(), frame->length(), frame->discard_padding(),
frame->track_number(), frame_timecode, frame->is_key())) {
@ -3085,7 +3085,7 @@ bool Segment::WriteFramesLessThan(uint64 timestamp) {
const uint64 frame_timecode = frame_timestamp / timecode_scale;
const int64 discard_padding = frame_prev->discard_padding();
if (discard_padding > 0) {
if (discard_padding != 0) {
if (!cluster->AddFrameWithDiscardPadding(
frame_prev->frame(), frame_prev->length(), discard_padding,
frame_prev->track_number(), frame_timecode,

22
mkvmuxerutil.cpp
View File

@ -72,6 +72,13 @@ int32 GetUIntSize(uint64 value) {
return 8;
}
int32 GetIntSize(int64 value) {
// Doubling the requested value ensures positive values with their high bit
// set are written with 0-padding to avoid flipping the signedness.
const uint64 v = (value < 0) ? value ^ -1LL : value;
return GetUIntSize(2 * v);
}
uint64 EbmlMasterElementSize(uint64 type, uint64 value) {
// Size of EBML ID
int32 ebml_size = GetUIntSize(type);
@ -83,7 +90,16 @@ uint64 EbmlMasterElementSize(uint64 type, uint64 value) {
}
uint64 EbmlElementSize(uint64 type, int64 value) {
return EbmlElementSize(type, static_cast<uint64>(value));
// Size of EBML ID
int32 ebml_size = GetUIntSize(type);
// Datasize
ebml_size += GetIntSize(value);
// Size of Datasize
ebml_size++;
return ebml_size;
}
uint64 EbmlElementSize(uint64 type, uint64 value) {
@ -592,7 +608,7 @@ uint64 WriteBlockWithDiscardPadding(IMkvWriter* writer, const uint8* data,
uint64 length, int64 discard_padding,
uint64 track_number, int64 timecode,
uint64 is_key) {
if (!data || length < 1 || discard_padding <= 0)
if (!data || length < 1)
return 0;
const uint64 block_payload_size = 4 + length;
@ -630,7 +646,7 @@ uint64 WriteBlockWithDiscardPadding(IMkvWriter* writer, const uint8* data,
if (WriteID(writer, kMkvDiscardPadding))
return 0;
const uint64 size = GetUIntSize(discard_padding);
const uint64 size = GetIntSize(discard_padding);
if (WriteUInt(writer, size))
return false;