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webm2pes: Fix super frame splitting.

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Super frame index is at the end of the frame; not the beginning. Adjust
length to process instead of offsetting the start point for breaking up
the super frame.

Change-Id: I71910f24cc060934bb974548a29617b985985ed9
This commit is contained in:
Tom Finegan
2015-12-17 08:38:43 -08:00
parent 3cb96b6e33
commit e8fca12fb6
1 changed files with 16 additions and 8 deletions
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24
common/libwebm_utils.cc
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@@ -19,29 +19,37 @@ std::int64_t NanosecondsTo90KhzTicks(std::int64_t nanoseconds) {
} }
bool ParseVP9SuperFrameIndex(const std::uint8_t* frame, bool ParseVP9SuperFrameIndex(const std::uint8_t* frame,
std::size_t length, std::size_t frame_length,
Ranges* frame_ranges) { Ranges* frame_ranges) {
if (frame == nullptr || length == 0 || frame_ranges == nullptr) if (frame == nullptr || frame_length == 0 || frame_ranges == nullptr)
return false; return false;
bool parse_ok = false; bool parse_ok = false;
const std::uint8_t marker = frame[length - 1]; const std::uint8_t marker = frame[frame_length - 1];
const std::uint32_t kHasSuperFrameIndexMask = 0xe0; const std::uint32_t kHasSuperFrameIndexMask = 0xe0;
const std::uint32_t kSuperFrameMarker = 0xc0; const std::uint32_t kSuperFrameMarker = 0xc0;
const std::uint32_t kLengthFieldSizeMask = 0x3;
if ((marker & kHasSuperFrameIndexMask) == kSuperFrameMarker) { if ((marker & kHasSuperFrameIndexMask) == kSuperFrameMarker) {
const std::uint32_t kFrameCountMask = 0x7; const std::uint32_t kFrameCountMask = 0x7;
const int num_frames = (marker & kFrameCountMask) + 1; const int num_frames = (marker & kFrameCountMask) + 1;
const int length_field_size = ((marker >> 3) & 0x3) + 1; const int length_field_size = ((marker >> 3) & kLengthFieldSizeMask) + 1;
const std::size_t index_length = 2 + length_field_size * num_frames; const std::size_t index_length = 2 + length_field_size * num_frames;
// Consume the super frame index. if (frame_length < index_length) {
std::size_t frame_offset = index_length; std::fprintf(stderr, "Webm2Pes: Invalid superframe index size.\n");
return false;
}
if (length >= index_length && frame[length - index_length] == marker) { // Consume the super frame index. Note: it's at the end of the super frame.
const std::size_t length = frame_length - index_length;
if (length >= index_length &&
frame[frame_length - index_length] == marker) {
// Found a valid superframe index. // Found a valid superframe index.
const std::uint8_t* byte = frame + length - index_length + 1; const std::uint8_t* byte = frame + length + 1;
std::size_t frame_offset = 0;
for (int i = 0; i < num_frames; ++i) { for (int i = 0; i < num_frames; ++i) {
std::uint32_t child_frame_length = 0; std::uint32_t child_frame_length = 0;