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Block align frames in superframe for vp9 cenc 

Change-Id: I065151c05d55c993ffbd0c30f2aa521e8476833c
This commit is contained in:
KongQun Yang 2016-01-04 16:18:34 -08:00
parent 7c61aa15ed
commit 458d376343
1 changed files with 14 additions and 0 deletions
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14
packager/media/formats/mp4/encrypting_fragmenter.cc
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@ -17,6 +17,7 @@
namespace { namespace {
// Generate 64bit IV by default. // Generate 64bit IV by default.
const size_t kDefaultIvSize = 8u; const size_t kDefaultIvSize = 8u;
const size_t kCencBlockSize = 16u;
} // namespace } // namespace
namespace edash_packager { namespace edash_packager {
@ -156,11 +157,24 @@ Status EncryptingFragmenter::EncryptSample(scoped_refptr<MediaSample> sample) {
&vpx_frames)) { &vpx_frames)) {
return Status(error::MUXER_FAILURE, "Failed to parse vpx frame."); return Status(error::MUXER_FAILURE, "Failed to parse vpx frame.");
} }
const bool is_superframe = vpx_frames.size() > 1;
for (const VPxFrameInfo& frame : vpx_frames) { for (const VPxFrameInfo& frame : vpx_frames) {
SubsampleEntry subsample; SubsampleEntry subsample;
subsample.clear_bytes = frame.uncompressed_header_size; subsample.clear_bytes = frame.uncompressed_header_size;
subsample.cipher_bytes = subsample.cipher_bytes =
frame.frame_size - frame.uncompressed_header_size; frame.frame_size - frame.uncompressed_header_size;
// "VP Codec ISO Media File Format Binding" document requires that the
// encrypted bytes of each frame within the superframe must be block
// aligned so that the counter state can be computed for each frame
// within the superframe.
if (is_superframe) {
uint16_t misalign_bytes = subsample.cipher_bytes % kCencBlockSize;
subsample.clear_bytes += misalign_bytes;
subsample.cipher_bytes -= misalign_bytes;
}
sample_encryption_entry.subsamples.push_back(subsample); sample_encryption_entry.subsamples.push_back(subsample);
if (subsample.cipher_bytes > 0) if (subsample.cipher_bytes > 0)
EncryptBytes(data + subsample.clear_bytes, subsample.cipher_bytes); EncryptBytes(data + subsample.clear_bytes, subsample.cipher_bytes);