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[Session] Rework of ExtractStreamProtectionData
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When init data or default KID is missing
this change allow to extract it from mp4 box

NOTE now this method is intended to never change the data from PSSHSets objects
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@CastagnaIT
CastagnaIT committed Aug 26, 2024
1 parent 6ece294 commit 25f92b1
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Showing 4 changed files with 102 additions and 66 deletions.
142 changes: 78 additions & 64 deletions src/Session.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -381,6 +381,11 @@ bool CSession::InitializeDRM(bool addDefaultKID /* = false */)
// cdmSession 0 is reserved for unencrypted streams
for (size_t ses{1}; ses < m_cdmSessions.size(); ++ses)
{
const CPeriod::PSSHSet& sessionPsshset = m_adaptiveTree->m_currentPeriod->GetPSSHSets()[ses];

if (sessionPsshset.adaptation_set_->GetStreamType() == StreamType::NOTYPE)
continue;

CCdmSession& session{m_cdmSessions[ses]};

// Check if the decrypter has been previously initialized, if so skip it,
Expand All @@ -392,15 +397,10 @@ bool CSession::InitializeDRM(bool addDefaultKID /* = false */)
if (session.m_cencSingleSampleDecrypter)
continue;

std::vector<uint8_t> initData;
std::vector<uint8_t> initData = sessionPsshset.pssh_;
std::string defaultKidStr = sessionPsshset.defaultKID_;
std::string drmOptionalKeyParam;

CPeriod::PSSHSet& sessionPsshset = m_adaptiveTree->m_currentPeriod->GetPSSHSets()[ses];

if (sessionPsshset.adaptation_set_->GetStreamType() == StreamType::NOTYPE)
continue;

const std::vector<uint8_t> defaultKid = DRM::ConvertKidStrToBytes(sessionPsshset.defaultKID_);
std::string_view licenseDataStr = CSrvBroker::GetKodiProps().GetLicenseData();

if (m_adaptiveTree->GetTreeType() == adaptive::TreeType::SMOOTH_STREAMING)
Expand All @@ -423,7 +423,7 @@ bool CSession::InitializeDRM(bool addDefaultKID /* = false */)
licenseData.empty() ? "" : "(with custom data)");

std::vector<uint8_t> wvPsshData;
if (DRM::MakeWidevinePsshData(defaultKid, licenseData, wvPsshData))
if (DRM::MakeWidevinePsshData(DRM::ConvertKidStrToBytes(defaultKidStr), licenseData, wvPsshData))
DRM::MakePssh(DRM::ID_WIDEVINE, wvPsshData, initData);
}
}
Expand Down Expand Up @@ -451,22 +451,17 @@ bool CSession::InitializeDRM(bool addDefaultKID /* = false */)
initData = BASE64::Decode(licenseDataStr);
}

if (initData.empty() && sessionPsshset.m_licenseUrl.empty())
//! @todo: as is implemented InitializeDRM will initialize all PSSHSet's also when are not used,
//! therefore ExtractStreamProtectionData can perform many (not needed) downloads of mp4 init files
if ((initData.empty() && licenseType != DRM::KS_CLEARKEY) || defaultKidStr.empty())
{
if (!sessionPsshset.pssh_.empty())
{
// Use the init data provided by manifest (e.g. PSSH)
initData = sessionPsshset.pssh_;
}
else if (licenseType != DRM::KS_CLEARKEY)
{
// Try extract the PSSH/KID from the stream
// only if clearkeys are not used (use case e.g. Widevine manifest tested with ClearKey DRM)
if (!ExtractStreamProtectionData(sessionPsshset, initData, m_adaptiveTree->m_supportedKeySystems))
LOG::Log(LOGERROR, "License data: Cannot extract PSSH/KID data from the stream");
}
// Try extract the PSSH/KID from the stream
ExtractStreamProtectionData(sessionPsshset, defaultKidStr, initData,
m_adaptiveTree->m_supportedKeySystems);
}

const std::vector<uint8_t> defaultKid = DRM::ConvertKidStrToBytes(defaultKidStr);

if (addDefaultKID && ses == 1 && session.m_cencSingleSampleDecrypter)
{
// If the CDM has been pre-initialized, on non-android systems
Expand All @@ -478,7 +473,7 @@ bool CSession::InitializeDRM(bool addDefaultKID /* = false */)

if (m_decrypter && !defaultKid.empty())
{
LOG::Log(LOGDEBUG, "Initializing stream with KID: %s", sessionPsshset.defaultKID_.c_str());
LOG::Log(LOGDEBUG, "Initializing stream with KID: %s", defaultKidStr.c_str());

for (size_t i{1}; i < ses; ++i)
{
Expand Down Expand Up @@ -1457,13 +1452,18 @@ bool CSession::SeekChapter(int ch)
return false;
}

bool CSession::ExtractStreamProtectionData(PLAYLIST::CPeriod::PSSHSet& sessionPsshset,
void CSession::ExtractStreamProtectionData(const PLAYLIST::CPeriod::PSSHSet& psshSet,
std::string& defaultKid,
std::vector<uint8_t>& initData,
std::vector<std::string_view> keySystems)
const std::vector<std::string_view>& keySystems)
{
auto initialRepr = m_reprChooser->GetRepresentation(sessionPsshset.adaptation_set_);
auto initialRepr = m_reprChooser->GetRepresentation(psshSet.adaptation_set_);

if (initialRepr->GetContainerType() != ContainerType::MP4)
return;

CStream stream{m_adaptiveTree, sessionPsshset.adaptation_set_, initialRepr};
LOG::LogF(LOGDEBUG, "Open stream to extract protection data...");
CStream stream{m_adaptiveTree, psshSet.adaptation_set_, initialRepr};

stream.m_isEnabled = true;
stream.m_adStream.start_stream();
Expand All @@ -1475,61 +1475,75 @@ bool CSession::ExtractStreamProtectionData(PLAYLIST::CPeriod::PSSHSet& sessionPs
{
LOG::LogF(LOGERROR, "No MOOV atom in stream");
stream.Disable();
return false;
return;
}
AP4_Array<AP4_PsshAtom>& pssh{movie->GetPsshAtoms()};

for (std::string_view keySystem : keySystems)
AP4_Track* track =
movie->GetTrack(static_cast<AP4_Track::Type>(stream.m_adStream.GetTrackType()));

if (track) // Try extract the default KID from tenc / piff mp4 box
{
std::vector<uint8_t> systemIdBytes;
STRING::ToHexBytes(DRM::UrnToSystemId(keySystem), systemIdBytes);
AP4_ProtectedSampleDescription* protSampleDesc =
static_cast<AP4_ProtectedSampleDescription*>(track->GetSampleDescription(0));

for (unsigned int i = 0; initData.size() == 0 && i < pssh.ItemCount(); i++)
if (protSampleDesc)
{
if (std::memcmp(pssh[i].GetSystemId(), systemIdBytes.data(), 16) == 0)
AP4_ProtectionSchemeInfo* psi = protSampleDesc->GetSchemeInfo();
if (psi)
{
const AP4_DataBuffer& dataBuf = pssh[i].GetData();

initData.insert(initData.end(), dataBuf.GetData(), dataBuf.GetData() + dataBuf.GetDataSize());

if (sessionPsshset.defaultKID_.empty())
AP4_ContainerAtom* schi = protSampleDesc->GetSchemeInfo()->GetSchiAtom();
if (schi)
{
if (pssh[i].GetKid(0))
AP4_TencAtom* tenc =
AP4_DYNAMIC_CAST(AP4_TencAtom, schi->GetChild(AP4_ATOM_TYPE_TENC, 0));
if (tenc)
{
sessionPsshset.defaultKID_ = std::string((const char*)pssh[i].GetKid(0), 16);
defaultKid = STRING::ToHexadecimal(tenc->GetDefaultKid(), 16);
}
else if (AP4_Track* track = movie->GetTrack(
static_cast<AP4_Track::Type>(stream.m_adStream.GetTrackType())))
else
{
AP4_ProtectedSampleDescription* m_protectedDesc =
static_cast<AP4_ProtectedSampleDescription*>(track->GetSampleDescription(0));
AP4_ContainerAtom* schi;
if (m_protectedDesc->GetSchemeInfo() &&
(schi = m_protectedDesc->GetSchemeInfo()->GetSchiAtom()))
AP4_PiffTrackEncryptionAtom* piff =
AP4_DYNAMIC_CAST(AP4_PiffTrackEncryptionAtom,
schi->GetChild(AP4_UUID_PIFF_TRACK_ENCRYPTION_ATOM, 0));
if (piff)
{
AP4_TencAtom* tenc{
AP4_DYNAMIC_CAST(AP4_TencAtom, schi->GetChild(AP4_ATOM_TYPE_TENC, 0)) };
if (tenc)
{
sessionPsshset.defaultKID_ = STRING::ToHexadecimal(tenc->GetDefaultKid(), 16);
}
else
{
AP4_PiffTrackEncryptionAtom* piff{
AP4_DYNAMIC_CAST(AP4_PiffTrackEncryptionAtom,
schi->GetChild(AP4_UUID_PIFF_TRACK_ENCRYPTION_ATOM, 0)) };
if (piff)
{
sessionPsshset.defaultKID_ = STRING::ToHexadecimal(piff->GetDefaultKid(), 16);
}
}
defaultKid = STRING::ToHexadecimal(piff->GetDefaultKid(), 16);
}
}
}
}
}
}

if (initData.empty() || defaultKid.empty())
{
const std::vector<std::string> systemIds = DRM::UrnsToSystemIds(keySystems);
AP4_Array<AP4_PsshAtom>& pssh{movie->GetPsshAtoms()};

for (unsigned int i = 0; i < pssh.ItemCount(); ++i)
{
AP4_PsshAtom& psshAtom = pssh[i];

std::string systemId = STRING::ToHexadecimal(psshAtom.GetSystemId(), 16);

// Find supported system id
if (std::find(systemIds.cbegin(), systemIds.cend(), systemId) != systemIds.cend())
{
const AP4_DataBuffer& dataBuf = psshAtom.GetData();
const std::vector<uint8_t> psshData{dataBuf.GetData(),
dataBuf.GetData() + dataBuf.GetDataSize()};

DRM::MakePssh(psshAtom.GetSystemId(), psshData, initData);

if (psshAtom.GetKid(0))
{
defaultKid = STRING::ToHexadecimal(pssh[i].GetKid(0), 16);
}

break;
}
}
}

stream.Disable();
return !initData.empty();
}
5 changes: 3 additions & 2 deletions src/Session.h
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Original file line number Diff line number Diff line change
Expand Up @@ -334,9 +334,10 @@ class ATTR_DLL_LOCAL CSession : public adaptive::AdaptiveStreamObserver
*/
void DisposeDecrypter();

bool ExtractStreamProtectionData(PLAYLIST::CPeriod::PSSHSet& sessionPsshset,
void ExtractStreamProtectionData(const PLAYLIST::CPeriod::PSSHSet& psshSet,
std::string& defaultKid,
std::vector<uint8_t>& initData,
std::vector<std::string_view> keySystems);
const std::vector<std::string_view>& keySystems);

private:
std::string m_manifestUrl;
Expand Down
14 changes: 14 additions & 0 deletions src/decrypters/Helpers.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -128,6 +128,20 @@ std::string DRM::UrnToSystemId(std::string_view urn)
return sysId;
}

std::vector<std::string> DRM::UrnsToSystemIds(const std::vector<std::string_view>& urns)
{
std::vector<std::string> sids;

for (std::string_view urn : urns)
{
std::string sid = DRM::UrnToSystemId(urn);
if (!sid.empty())
sids.emplace_back(DRM::UrnToSystemId(urn));
}

return sids;
}

bool DRM::IsKeySystemSupported(std::string_view keySystem)
{
return keySystem == DRM::KS_NONE || keySystem == DRM::KS_WIDEVINE ||
Expand Down
7 changes: 7 additions & 0 deletions src/decrypters/Helpers.h
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,13 @@ std::string GenerateUrlDomainHash(std::string_view url);
*/
std::string UrnToSystemId(std::string_view urn);

/*!
* \brief Convert a list of DRM URN's to System ID's.
* \param urn The URN
* \return The System ID's, failed conversions are not included.
*/
std::vector<std::string> UrnsToSystemIds(const std::vector<std::string_view>& urns);

/*!
* \brief Convert a hexdecimal KeyId of 32 chars to 16 bytes.
* \param kidStr The hexdecimal KeyId
Expand Down

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