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Add support to output sub-sample encryption information.

Browse Source 
See http://wiki.webmproject.org/encryption/webm-subsample-encryption
for the format.

Change-Id: Ia5d6f3566b92c46911704108d3e86cd0fac9ee34
This commit is contained in:
Frank Galligan
2016-09-16 09:19:00 -07:00
parent 26f434423f
commit c97e3e7d60
3 changed files with 95 additions and 7 deletions
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57
webm_info.cc
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@@ -788,6 +788,39 @@ void PrintVP8Info(const uint8_t* data, int size, FILE* o) {
altref_frame, partition_length);
}
// Prints the partition offsets of the sub-sample encryption. |data| must point
// to an encrypted frame just after the signal byte. Returns the number of
// bytes read from the sub-sample partition information.
int PrintSubSampleEncryption(const uint8_t* data, int size, FILE* o) {
int read_end = sizeof(uint64_t);
// Skip past IV.
if (size < read_end)
return 0;
data += sizeof(uint64_t);
// Read number of partitions.
read_end += sizeof(uint8_t);
if (size < read_end)
return 0;
const int num_partitions = data[0];
data += sizeof(uint8_t);
// Read partitions.
for (int i = 0; i < num_partitions; ++i) {
read_end += sizeof(uint32_t);
if (size < read_end)
return 0;
uint32_t partition_offset;
memcpy(&partition_offset, data, sizeof(partition_offset));
partition_offset = libwebm::bigendian_to_host(partition_offset);
fprintf(o, " off[%d]:%u", i, partition_offset);
data += sizeof(uint32_t);
}
return read_end;
}
bool OutputCluster(const mkvparser::Cluster& cluster,
const mkvparser::Tracks& tracks, const Options& options,
FILE* o, mkvparser::MkvReader* reader, Indent* indent,
@@ -883,6 +916,7 @@ bool OutputCluster(const mkvparser::Cluster& cluster,
fprintf(o, " size_payload: %lld", block->m_size);
const uint8_t KEncryptedBit = 0x1;
const uint8_t kSubSampleBit = 0x2;
const int kSignalByteSize = 1;
bool encrypted_stream = false;
if (options.output_encrypted_info) {
@@ -917,8 +951,10 @@ bool OutputCluster(const mkvparser::Cluster& cluster,
return false;
}
const bool encrypted_frame = (data[0] & KEncryptedBit) ? 1 : 0;
const bool encrypted_frame = !!(data[0] & KEncryptedBit);
const bool sub_sample_encrypt = !!(data[0] & kSubSampleBit);
fprintf(o, " enc: %d", encrypted_frame ? 1 : 0);
fprintf(o, " sub: %d", sub_sample_encrypt ? 1 : 0);
if (encrypted_frame) {
uint64_t iv;
@@ -953,24 +989,35 @@ bool OutputCluster(const mkvparser::Cluster& cluster,
fprintf(o, "\n%sVP8 data :", indent->indent_str().c_str());
bool encrypted_frame = false;
bool sub_sample_encrypt = false;
int frame_size = static_cast<int>(frame.len);
int frame_offset = 0;
if (encrypted_stream) {
if (data[0] & KEncryptedBit) {
encrypted_frame = true;
if (data[0] & kSubSampleBit) {
sub_sample_encrypt = true;
data += kSignalByteSize;
frame_size -= kSignalByteSize;
frame_offset =
PrintSubSampleEncryption(data, frame_size, o);
}
} else {
frame_offset = kSignalByteSize;
}
}
if (!encrypted_frame) {
if (!encrypted_frame || sub_sample_encrypt) {
data += frame_offset;
frame_size -= frame_offset;
const string codec_id = track->GetCodecId();
if (codec_id == "V_VP8") {
PrintVP8Info(data, static_cast<int>(frame.len), o);
PrintVP8Info(data, frame_size, o);
} else if (codec_id == "V_VP9") {
PrintVP9Info(data, static_cast<int>(frame.len), o, time_ns,
stats, parser, level_stats);
PrintVP9Info(data, frame_size, o, time_ns, stats, parser,
level_stats);
}
}
}