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Support Latest Version of EME Spec Init Data Specification

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(This is a merge of
https://widevine-internal-review.googlesource.com/9711 from the
Widevine CDM repo.)

This change updates the CDM's handling of init data types, previously
known as MIME types, to comply with the latest version of the EME
spec.

Following this change, in addition to accepting the deprecated MIME
types "video/mp4", "audio/mp4", "video/webm", and "audio/webm", the
CDM will accept the new standard: Init data types "cenc" and "webm".

Furthermore, this removes the non-PSSH-parsing path from the CDM. All
platforms have unified on the CDM being responsible for parsing the
concatenated PSSH box list, as outlined in the latest EME spec.

As Android has shipped code that expects pre-unwrapped PSSH boxes and
must maintain backwards-compatibility, code has been inserted on that
platform to detect pre-unwrapped data and re-wrap it with a PSSH
header before sending it to the CDM.

There are some small changes to unit tests because of this change:

1) The CDM Engine unit test now no longer needs to unwrap the PSSH on
   any platforms when testing ISO-BMFF. It now pre-caches the
   unwrapped key ID for use when testing WebM.

2) Several substantially-similar unit tests in the Android code have
   been rolled into one test.

Bug: 13564917
Bug: 13570595
Bug: 9465346
Bug: 13570288
Change-Id: I7f27b16b8503f24a26746b5dce71fb61b6fd1bb2
This commit is contained in:
John "Juce" Bruce
2014-04-09 17:51:42 -07:00
committed by John Bruce
parent de6f6f6324
commit 951f08c2da
13 changed files with 166 additions and 213 deletions
Download Patch File Download Diff File Expand all files Collapse all files

52
libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp
View File

@@ -19,16 +19,20 @@
#include "utils/Errors.h"
#include "wv_cdm_constants.h"
namespace {
static const char* const kResetSecurityLevel = "";
static const char* const kEnable = "enable";
static const char* const kDisable = "disable";
static const std::string kPsshTag = "pssh";
}
namespace wvdrm {
using namespace android;
using namespace std;
using namespace wvcdm;
static const char* const kResetSecurityLevel = "";
static const char* const kEnable = "enable";
static const char* const kDisable = "disable";
WVDrmPlugin::WVDrmPlugin(WvContentDecryptionModule* cdm,
WVGenericCryptoInterface* crypto)
: mCDM(cdm), mCrypto(crypto) {}
@@ -149,21 +153,18 @@ status_t WVDrmPlugin::getKeyRequest(
return android::ERROR_DRM_CANNOT_HANDLE;
}
string cdmMimeType = initDataType.string();
string cdmInitDataType = initDataType.string();
// Provide backwards-compatibility for apps that pass non-EME-compatible MIME
// types.
if (cdmMimeType != wvcdm::ISO_BMFF_VIDEO_MIME_TYPE &&
cdmMimeType != wvcdm::ISO_BMFF_AUDIO_MIME_TYPE &&
cdmMimeType != wvcdm::WEBM_VIDEO_MIME_TYPE &&
cdmMimeType != wvcdm::WEBM_AUDIO_MIME_TYPE) {
cdmMimeType = wvcdm::ISO_BMFF_VIDEO_MIME_TYPE;
if (!WvContentDecryptionModule::IsSupported(cdmInitDataType)) {
cdmInitDataType = wvcdm::ISO_BMFF_VIDEO_MIME_TYPE;
}
CdmInitData processedInitData;
if (cdmMimeType == wvcdm::ISO_BMFF_VIDEO_MIME_TYPE ||
cdmMimeType == wvcdm::ISO_BMFF_AUDIO_MIME_TYPE) {
// For ISO-BMFF, we need to wrap the init data in a new PSSH header.
if (WvContentDecryptionModule::IsCenc(cdmInitDataType) &&
!InitDataResemblesPSSH(initData)) {
// This data was passed in the old format, pre-unwrapped. We need to wrap
// the init data in a new PSSH header.
static const char psshPrefix[] = {
0, 0, 0, 0, // Total size
'p', 's', 's', 'h', // "PSSH"
@@ -204,7 +205,8 @@ status_t WVDrmPlugin::getKeyRequest(
CdmKeyMessage keyRequest;
string cdmDefaultUrl;
CdmResponseType res = mCDM->GenerateKeyRequest(cdmSessionId, cdmKeySetId,
cdmMimeType, processedInitData,
cdmInitDataType,
processedInitData,
cdmLicenseType, cdmParameters,
&keyRequest, &cdmDefaultUrl);
@@ -929,4 +931,24 @@ status_t WVDrmPlugin::mapOEMCryptoResult(OEMCryptoResult res) {
}
}
bool WVDrmPlugin::InitDataResemblesPSSH(const Vector<uint8_t>& initData) {
const uint8_t* const initDataArray = initData.array();
// Extract the size field
const uint8_t* const sizeField = &initDataArray[0];
uint32_t nboSize;
memcpy(&nboSize, sizeField, sizeof(nboSize));
uint32_t size = ntohl(nboSize);
if (size > initData.size()) {
return false;
}
// Extract the ID field
const char* const idField =
reinterpret_cast<const char* const>(&initDataArray[sizeof(nboSize)]);
string id(idField, kPsshTag.size());
return id == kPsshTag;
}
} // namespace wvdrm