ref: 9a9fa10c760b59e48c567d408de3878498755f84
dir: /common/mp4v2/isma.cpp/
/* * The contents of this file are subject to the Mozilla Public * License Version 1.1 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy of * the License at http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * The Original Code is MPEG4IP. * * The Initial Developer of the Original Code is Cisco Systems Inc. * Portions created by Cisco Systems Inc. are * Copyright (C) Cisco Systems Inc. 2001. All Rights Reserved. * * Contributor(s): * Dave Mackie [email protected] */ #include "mp4common.h" static u_int8_t BifsV2Config[3] = { 0x00, 0x00, 0x40 // IsCommandStream }; void MP4File::MakeIsmaCompliant(bool addIsmaComplianceSdp) { ProtectWriteOperation("MP4MakeIsmaCompliant"); if (m_useIsma) { // already done return; } m_useIsma = true; // find first audio and/or video tracks MP4TrackId audioTrackId = MP4_INVALID_TRACK_ID; try { audioTrackId = FindTrackId(0, MP4_AUDIO_TRACK_TYPE); } catch (MP4Error* e) { delete e; } MP4TrackId videoTrackId = MP4_INVALID_TRACK_ID; try { videoTrackId = FindTrackId(0, MP4_VIDEO_TRACK_TYPE); } catch (MP4Error* e) { delete e; } u_int64_t fileMsDuration = ConvertFromMovieDuration(GetDuration(), MP4_MSECS_TIME_SCALE); // delete any existing OD track if (m_odTrackId != MP4_INVALID_TRACK_ID) { DeleteTrack(m_odTrackId); } AddODTrack(); SetODProfileLevel(0xFF); if (audioTrackId != MP4_INVALID_TRACK_ID) { AddTrackToOd(audioTrackId); } if (videoTrackId != MP4_INVALID_TRACK_ID) { AddTrackToOd(videoTrackId); } // delete any existing scene track MP4TrackId sceneTrackId = MP4_INVALID_TRACK_ID; try { sceneTrackId = FindTrackId(0, MP4_SCENE_TRACK_TYPE); } catch (MP4Error *e) { delete e; } if (sceneTrackId != MP4_INVALID_TRACK_ID) { DeleteTrack(sceneTrackId); } // add scene track sceneTrackId = AddSceneTrack(); SetSceneProfileLevel(0xFF); SetGraphicsProfileLevel(0xFF); SetTrackIntegerProperty(sceneTrackId, "mdia.minf.stbl.stsd.mp4s.esds.decConfigDescr.objectTypeId", MP4SystemsV2ObjectType); SetTrackESConfiguration(sceneTrackId, BifsV2Config, sizeof(BifsV2Config)); u_int8_t* pBytes = NULL; u_int64_t numBytes = 0; // write OD Update Command CreateIsmaODUpdateCommandFromFileForFile( m_odTrackId, audioTrackId, videoTrackId, &pBytes, &numBytes); WriteSample(m_odTrackId, pBytes, numBytes, fileMsDuration); MP4Free(pBytes); pBytes = NULL; // write BIFS Scene Replace Command CreateIsmaSceneCommand( MP4_IS_VALID_TRACK_ID(audioTrackId), MP4_IS_VALID_TRACK_ID(videoTrackId), &pBytes, &numBytes); WriteSample(sceneTrackId, pBytes, numBytes, fileMsDuration); MP4Free(pBytes); pBytes = NULL; // add session level sdp CreateIsmaIodFromFile( m_odTrackId, sceneTrackId, audioTrackId, videoTrackId, &pBytes, &numBytes); char* iodBase64 = MP4ToBase64(pBytes, numBytes); char* sdpBuf = (char*)MP4Calloc(strlen(iodBase64) + 256); if (addIsmaComplianceSdp) { strcpy(sdpBuf, "a=isma-compliance:1,1.0,1\015\012"); } sprintf(&sdpBuf[strlen(sdpBuf)], "a=mpeg4-iod: \042data:application/mpeg4-iod;base64,%s\042\015\012", iodBase64); SetSessionSdp(sdpBuf); VERBOSE_ISMA(GetVerbosity(), printf("IOD SDP = %s\n", sdpBuf)); MP4Free(iodBase64); iodBase64 = NULL; MP4Free(pBytes); pBytes = NULL; MP4Free(sdpBuf); sdpBuf = NULL; } static void CloneIntegerProperty( MP4Descriptor* pDest, MP4DescriptorProperty* pSrc, const char* name) { MP4IntegerProperty* pGetProperty; MP4IntegerProperty* pSetProperty; pSrc->FindProperty(name, (MP4Property**)&pGetProperty); pDest->FindProperty(name, (MP4Property**)&pSetProperty); pSetProperty->SetValue(pGetProperty->GetValue()); } void MP4File::CreateIsmaIodFromFile( MP4TrackId odTrackId, MP4TrackId sceneTrackId, MP4TrackId audioTrackId, MP4TrackId videoTrackId, u_int8_t** ppBytes, u_int64_t* pNumBytes) { MP4Descriptor* pIod = new MP4IODescriptor(); pIod->SetTag(MP4IODescrTag); pIod->Generate(); MP4Atom* pIodsAtom = FindAtom("moov.iods"); ASSERT(pIodsAtom); MP4DescriptorProperty* pSrcIod = (MP4DescriptorProperty*)pIodsAtom->GetProperty(2); CloneIntegerProperty(pIod, pSrcIod, "objectDescriptorId"); CloneIntegerProperty(pIod, pSrcIod, "ODProfileLevelId"); CloneIntegerProperty(pIod, pSrcIod, "sceneProfileLevelId"); CloneIntegerProperty(pIod, pSrcIod, "audioProfileLevelId"); CloneIntegerProperty(pIod, pSrcIod, "visualProfileLevelId"); CloneIntegerProperty(pIod, pSrcIod, "graphicsProfileLevelId"); // mutate esIds from MP4ESIDIncDescrTag to MP4ESDescrTag MP4DescriptorProperty* pEsProperty; pIod->FindProperty("esIds", (MP4Property**)&pEsProperty); pEsProperty->SetTags(MP4ESDescrTag); MP4IntegerProperty* pSetProperty; // OD MP4Descriptor* pOdEsd = pEsProperty->AddDescriptor(MP4ESDescrTag); pOdEsd->Generate(); pOdEsd->FindProperty("ESID", (MP4Property**)&pSetProperty); pSetProperty->SetValue(m_odTrackId); pOdEsd->FindProperty("URLFlag", (MP4Property**)&pSetProperty); pSetProperty->SetValue(1); u_int8_t* pBytes; u_int64_t numBytes; CreateIsmaODUpdateCommandFromFileForStream( audioTrackId, videoTrackId, &pBytes, &numBytes); VERBOSE_ISMA(GetVerbosity(), printf("OD data =\n"); MP4HexDump(pBytes, numBytes)); char* odCmdBase64 = MP4ToBase64(pBytes, numBytes); char* urlBuf = (char*)MP4Malloc(strlen(odCmdBase64) + 64); sprintf(urlBuf, "data:application/mpeg4-od-au;base64,%s", odCmdBase64); MP4StringProperty* pUrlProperty; pOdEsd->FindProperty("URL", (MP4Property**)&pUrlProperty); pUrlProperty->SetValue(urlBuf); VERBOSE_ISMA(GetVerbosity(), printf("OD data URL = \042%s\042\n", urlBuf)); MP4Free(odCmdBase64); odCmdBase64 = NULL; MP4Free(pBytes); pBytes = NULL; MP4Free(urlBuf); urlBuf = NULL; MP4DescriptorProperty* pSrcDcd = NULL; // HACK temporarily point to scene decoder config FindProperty(MakeTrackName(odTrackId, "mdia.minf.stbl.stsd.mp4s.esds.decConfigDescr"), (MP4Property**)&pSrcDcd); ASSERT(pSrcDcd); MP4Property* pOrgOdEsdProperty = pOdEsd->GetProperty(8); pOdEsd->SetProperty(8, pSrcDcd); // bufferSizeDB needs to be set appropriately MP4BitfieldProperty* pBufferSizeProperty = NULL; pOdEsd->FindProperty("decConfigDescr.bufferSizeDB", (MP4Property**)&pBufferSizeProperty); ASSERT(pBufferSizeProperty); pBufferSizeProperty->SetValue(numBytes); // SL config needs to change from 2 (file) to 1 (null) pOdEsd->FindProperty("slConfigDescr.predefined", (MP4Property**)&pSetProperty); pSetProperty->SetValue(1); // Scene MP4Descriptor* pSceneEsd = pEsProperty->AddDescriptor(MP4ESDescrTag); pSceneEsd->Generate(); pSceneEsd->FindProperty("ESID", (MP4Property**)&pSetProperty); pSetProperty->SetValue(sceneTrackId); pSceneEsd->FindProperty("URLFlag", (MP4Property**)&pSetProperty); pSetProperty->SetValue(1); CreateIsmaSceneCommand( MP4_IS_VALID_TRACK_ID(audioTrackId), MP4_IS_VALID_TRACK_ID(videoTrackId), &pBytes, &numBytes); VERBOSE_ISMA(GetVerbosity(), printf("Scene data =\n"); MP4HexDump(pBytes, numBytes)); char *sceneCmdBase64 = MP4ToBase64(pBytes, numBytes); urlBuf = (char*)MP4Malloc(strlen(sceneCmdBase64) + 64); sprintf(urlBuf, "data:application/mpeg4-bifs-au;base64,%s", sceneCmdBase64); pSceneEsd->FindProperty("URL", (MP4Property**)&pUrlProperty); pUrlProperty->SetValue(urlBuf); VERBOSE_ISMA(GetVerbosity(), printf("Scene data URL = \042%s\042\n", urlBuf)); MP4Free(sceneCmdBase64); sceneCmdBase64 = NULL; MP4Free(urlBuf); urlBuf = NULL; MP4Free(pBytes); pBytes = NULL; // HACK temporarily point to scene decoder config FindProperty(MakeTrackName(sceneTrackId, "mdia.minf.stbl.stsd.mp4s.esds.decConfigDescr"), (MP4Property**)&pSrcDcd); ASSERT(pSrcDcd); MP4Property* pOrgSceneEsdProperty = pSceneEsd->GetProperty(8); pSceneEsd->SetProperty(8, pSrcDcd); // bufferSizeDB needs to be set pBufferSizeProperty = NULL; pSceneEsd->FindProperty("decConfigDescr.bufferSizeDB", (MP4Property**)&pBufferSizeProperty); ASSERT(pBufferSizeProperty); pBufferSizeProperty->SetValue(numBytes); // SL config needs to change from 2 (file) to 1 (null) pSceneEsd->FindProperty("slConfigDescr.predefined", (MP4Property**)&pSetProperty); pSetProperty->SetValue(1); // finally get the whole thing written to a memory pIod->WriteToMemory(this, ppBytes, pNumBytes); // now carefully replace esd properties before destroying pOdEsd->SetProperty(8, pOrgOdEsdProperty); pSceneEsd->SetProperty(8, pOrgSceneEsdProperty); delete pIod; VERBOSE_ISMA(GetVerbosity(), printf("IOD data =\n"); MP4HexDump(*ppBytes, *pNumBytes)); } void MP4File::CreateIsmaIodFromParams( u_int8_t videoProfile, u_int32_t videoBitrate, u_int8_t* videoConfig, u_int32_t videoConfigLength, u_int8_t audioProfile, u_int32_t audioBitrate, u_int8_t* audioConfig, u_int32_t audioConfigLength, u_int8_t** ppIodBytes, u_int64_t* pIodNumBytes) { MP4IntegerProperty* pInt; u_int8_t* pBytes = NULL; u_int64_t numBytes; // Create the IOD MP4Descriptor* pIod = new MP4IODescriptor(); pIod->SetTag(MP4IODescrTag); pIod->Generate(); // Set audio and video profileLevels pIod->FindProperty("audioProfileLevelId", (MP4Property**)&pInt); pInt->SetValue(audioProfile); pIod->FindProperty("visualProfileLevelId", (MP4Property**)&pInt); pInt->SetValue(videoProfile); // Mutate esIds from MP4ESIDIncDescrTag to MP4ESDescrTag MP4DescriptorProperty* pEsProperty; pIod->FindProperty("esIds", (MP4Property**)&pEsProperty); pEsProperty->SetTags(MP4ESDescrTag); // Add ES Descriptors // Scene CreateIsmaSceneCommand( (audioProfile != 0xFF), (videoProfile != 0xFF), &pBytes, &numBytes); VERBOSE_ISMA(GetVerbosity(), printf("Scene data =\n"); MP4HexDump(pBytes, numBytes)); char* sceneCmdBase64 = MP4ToBase64(pBytes, numBytes); char* urlBuf = (char*)MP4Malloc(strlen(sceneCmdBase64) + 64); sprintf(urlBuf, "data:application/mpeg4-bifs-au;base64,%s", sceneCmdBase64); VERBOSE_ISMA(GetVerbosity(), printf("Scene data URL = \042%s\042\n", urlBuf)); MP4Descriptor* pSceneEsd = CreateESD( pEsProperty, 201, // esid MP4SystemsV2ObjectType, MP4SceneDescriptionStreamType, numBytes, // bufferSize numBytes * 8, // bitrate BifsV2Config, sizeof(BifsV2Config), urlBuf); MP4Free(sceneCmdBase64); sceneCmdBase64 = NULL; MP4Free(urlBuf); urlBuf = NULL; MP4Free(pBytes); pBytes = NULL; // Video MP4Descriptor* pVideoEsd = CreateESD( pEsProperty, 20, // esid MP4_MPEG4_VIDEO_TYPE, MP4VisualStreamType, videoBitrate / 8, // bufferSize videoBitrate, videoConfig, videoConfigLength, NULL); // Audio MP4Descriptor* pAudioEsd = CreateESD( pEsProperty, 10, // esid MP4_MPEG4_AUDIO_TYPE, MP4AudioStreamType, audioBitrate / 8, // bufferSize audioBitrate, audioConfig, audioConfigLength, NULL); // OD // Glop to make infrastructure happy MP4DescriptorProperty* pAudioEsdProperty = new MP4DescriptorProperty(); pAudioEsdProperty->AppendDescriptor(pAudioEsd); MP4DescriptorProperty* pVideoEsdProperty = new MP4DescriptorProperty(); pVideoEsdProperty->AppendDescriptor(pVideoEsd); CreateIsmaODUpdateCommandForStream( pAudioEsdProperty, pVideoEsdProperty, &pBytes, &numBytes); // TBD cleanup temporary descriptor properties VERBOSE_ISMA(GetVerbosity(), printf("OD data =\n"); MP4HexDump(pBytes, numBytes)); char* odCmdBase64 = MP4ToBase64(pBytes, numBytes); urlBuf = (char*)MP4Malloc(strlen(odCmdBase64) + 64); sprintf(urlBuf, "data:application/mpeg4-od-au;base64,%s", odCmdBase64); VERBOSE_ISMA(GetVerbosity(), printf("OD data URL = \042%s\042\n", urlBuf)); MP4Descriptor* pOdEsd = CreateESD( pEsProperty, 101, MP4SystemsV1ObjectType, MP4ObjectDescriptionStreamType, numBytes, // bufferSize numBytes * 8, // bitrate NULL, // config 0, // configLength urlBuf); MP4Free(odCmdBase64); odCmdBase64 = NULL; MP4Free(pBytes); pBytes = NULL; MP4Free(urlBuf); urlBuf = NULL; // finally get the whole thing written to a memory pIod->WriteToMemory(this, ppIodBytes, pIodNumBytes); delete pIod; VERBOSE_ISMA(GetVerbosity(), printf("IOD data =\n"); MP4HexDump(*ppIodBytes, *pIodNumBytes)); } MP4Descriptor* MP4File::CreateESD( MP4DescriptorProperty* pEsProperty, u_int32_t esid, u_int8_t objectType, u_int8_t streamType, u_int32_t bufferSize, u_int32_t bitrate, u_int8_t* pConfig, u_int32_t configLength, char* url) { MP4IntegerProperty* pInt; MP4StringProperty* pString; MP4BytesProperty* pBytes; MP4Descriptor* pEsd = pEsProperty->AddDescriptor(MP4ESDescrTag); pEsd->Generate(); pEsd->FindProperty("ESID", (MP4Property**)&pInt); pInt->SetValue(esid); pEsd->FindProperty("decConfigDescr.objectTypeId", (MP4Property**)&pInt); pInt->SetValue(objectType); pEsd->FindProperty("decConfigDescr.streamType", (MP4Property**)&pInt); pInt->SetValue(streamType); pEsd->FindProperty("decConfigDescr.bufferSizeDB", (MP4Property**)&pInt); pInt->SetValue(bufferSize); pEsd->FindProperty("decConfigDescr.maxBitrate", (MP4Property**)&pInt); pInt->SetValue(bitrate); pEsd->FindProperty("decConfigDescr.avgBitrate", (MP4Property**)&pInt); pInt->SetValue(bitrate); MP4DescriptorProperty* pConfigDescrProperty; pEsd->FindProperty("decConfigDescr.decSpecificInfo", (MP4Property**)&pConfigDescrProperty); MP4Descriptor* pConfigDescr = pConfigDescrProperty->AddDescriptor(MP4DecSpecificDescrTag); pConfigDescr->Generate(); pConfigDescrProperty->FindProperty("decSpecificInfo[0].info", (MP4Property**)&pBytes); pBytes->SetValue(pConfig, configLength); pEsd->FindProperty("slConfigDescr.predefined", (MP4Property**)&pInt); pInt->SetValue(1); if (url) { pEsd->FindProperty("URLFlag", (MP4Property**)&pInt); pInt->SetValue(1); pEsd->FindProperty("URL", (MP4Property**)&pString); pString->SetValue(url); } return pEsd; } void MP4File::CreateIsmaODUpdateCommandFromFileForFile( MP4TrackId odTrackId, MP4TrackId audioTrackId, MP4TrackId videoTrackId, u_int8_t** ppBytes, u_int64_t* pNumBytes) { MP4Descriptor* pCommand = CreateODCommand(MP4ODUpdateODCommandTag); pCommand->Generate(); for (u_int8_t i = 0; i < 2; i++) { MP4TrackId trackId; u_int16_t odId; if (i == 0) { trackId = audioTrackId; odId = 10; } else { trackId = videoTrackId; odId = 20; } if (trackId == MP4_INVALID_TRACK_ID) { continue; } MP4DescriptorProperty* pOdDescrProperty = (MP4DescriptorProperty*)(pCommand->GetProperty(0)); pOdDescrProperty->SetTags(MP4FileODescrTag); MP4Descriptor* pOd = pOdDescrProperty->AddDescriptor(MP4FileODescrTag); pOd->Generate(); MP4BitfieldProperty* pOdIdProperty = NULL; pOd->FindProperty("objectDescriptorId", (MP4Property**)&pOdIdProperty); pOdIdProperty->SetValue(odId); MP4DescriptorProperty* pEsIdsDescriptorProperty = NULL; pOd->FindProperty("esIds", (MP4Property**)&pEsIdsDescriptorProperty); ASSERT(pEsIdsDescriptorProperty); pEsIdsDescriptorProperty->SetTags(MP4ESIDRefDescrTag); MP4Descriptor *pRefDescriptor = pEsIdsDescriptorProperty->AddDescriptor(MP4ESIDRefDescrTag); pRefDescriptor->Generate(); MP4Integer16Property* pRefIndexProperty = NULL; pRefDescriptor->FindProperty("refIndex", (MP4Property**)&pRefIndexProperty); ASSERT(pRefIndexProperty); u_int32_t mpodIndex = FindTrackReference( MakeTrackName(odTrackId, "tref.mpod"), trackId); ASSERT(mpodIndex != 0); pRefIndexProperty->SetValue(mpodIndex); } pCommand->WriteToMemory(this, ppBytes, pNumBytes); delete pCommand; } void MP4File::CreateIsmaODUpdateCommandFromFileForStream( MP4TrackId audioTrackId, MP4TrackId videoTrackId, u_int8_t** ppBytes, u_int64_t* pNumBytes) { MP4DescriptorProperty* pAudioEsd = NULL; MP4Integer8Property* pAudioSLConfig = NULL; MP4DescriptorProperty* pVideoEsd = NULL; MP4Integer8Property* pVideoSLConfig = NULL; if (audioTrackId != MP4_INVALID_TRACK_ID) { MP4Atom* pEsdsAtom = FindAtom(MakeTrackName(audioTrackId, "mdia.minf.stbl.stsd.mp4a.esds")); ASSERT(pEsdsAtom); pAudioEsd = (MP4DescriptorProperty*)(pEsdsAtom->GetProperty(2)); // SL config needs to change from 2 (file) to 1 (null) pAudioEsd->FindProperty("slConfigDescr.predefined", (MP4Property**)&pAudioSLConfig); ASSERT(pAudioSLConfig); pAudioSLConfig->SetValue(1); } if (videoTrackId != MP4_INVALID_TRACK_ID) { MP4Atom* pEsdsAtom = FindAtom(MakeTrackName(videoTrackId, "mdia.minf.stbl.stsd.mp4v.esds")); ASSERT(pEsdsAtom); pVideoEsd = (MP4DescriptorProperty*)(pEsdsAtom->GetProperty(2)); // SL config needs to change from 2 (file) to 1 (null) pVideoEsd->FindProperty("slConfigDescr.predefined", (MP4Property**)&pVideoSLConfig); ASSERT(pVideoSLConfig); pVideoSLConfig->SetValue(1); } CreateIsmaODUpdateCommandForStream( pAudioEsd, pVideoEsd, ppBytes, pNumBytes); // return SL config values to 2 (file) if (pAudioSLConfig) { pAudioSLConfig->SetValue(2); } if (pVideoSLConfig) { pVideoSLConfig->SetValue(2); } } void MP4File::CreateIsmaODUpdateCommandForStream( MP4DescriptorProperty* pAudioEsdProperty, MP4DescriptorProperty* pVideoEsdProperty, u_int8_t** ppBytes, u_int64_t* pNumBytes) { MP4Descriptor* pAudioOd = NULL; MP4Descriptor* pVideoOd = NULL; MP4Descriptor* pCommand = CreateODCommand(MP4ODUpdateODCommandTag); pCommand->Generate(); for (u_int8_t i = 0; i < 2; i++) { u_int16_t odId; MP4DescriptorProperty* pEsdProperty = NULL; if (i == 0) { odId = 10; pEsdProperty = pAudioEsdProperty; } else { odId = 20; pEsdProperty = pVideoEsdProperty; } if (pEsdProperty == NULL) { continue; } MP4DescriptorProperty* pOdDescrProperty = (MP4DescriptorProperty*)(pCommand->GetProperty(0)); pOdDescrProperty->SetTags(MP4ODescrTag); MP4Descriptor* pOd = pOdDescrProperty->AddDescriptor(MP4ODescrTag); pOd->Generate(); if (i == 0) { pAudioOd = pOd; } else { pVideoOd = pOd; } MP4BitfieldProperty* pOdIdProperty = NULL; pOd->FindProperty("objectDescriptorId", (MP4Property**)&pOdIdProperty); pOdIdProperty->SetValue(odId); delete (MP4DescriptorProperty*)pOd->GetProperty(4); pOd->SetProperty(4, pEsdProperty); } // serialize OD command pCommand->WriteToMemory(this, ppBytes, pNumBytes); // detach from esd descriptor params if (pAudioOd) { pAudioOd->SetProperty(4, NULL); } if (pVideoOd) { pVideoOd->SetProperty(4, NULL); } // then destroy delete pCommand; } void MP4File::CreateIsmaSceneCommand( bool hasAudio, bool hasVideo, u_int8_t** ppBytes, u_int64_t* pNumBytes) { // from ISMA 1.0 Tech Spec Appendix E static u_int8_t bifsAudioOnly[] = { 0xC0, 0x10, 0x12, 0x81, 0x30, 0x2A, 0x05, 0x7C }; static u_int8_t bifsVideoOnly[] = { 0xC0, 0x10, 0x12, 0x61, 0x04, 0x88, 0x50, 0x45, 0x05, 0x3F, 0x00 }; static u_int8_t bifsAudioVideo[] = { 0xC0, 0x10, 0x12, 0x81, 0x30, 0x2A, 0x05, 0x72, 0x61, 0x04, 0x88, 0x50, 0x45, 0x05, 0x3F, 0x00 }; if (hasAudio && hasVideo) { *pNumBytes = sizeof(bifsAudioVideo); *ppBytes = (u_int8_t*)MP4Malloc(*pNumBytes); memcpy(*ppBytes, bifsAudioVideo, sizeof(bifsAudioVideo)); } else if (hasAudio) { *pNumBytes = sizeof(bifsAudioOnly); *ppBytes = (u_int8_t*)MP4Malloc(*pNumBytes); memcpy(*ppBytes, bifsAudioOnly, sizeof(bifsAudioOnly)); } else if (hasVideo) { *pNumBytes = sizeof(bifsVideoOnly); *ppBytes = (u_int8_t*)MP4Malloc(*pNumBytes); memcpy(*ppBytes, bifsVideoOnly, sizeof(bifsVideoOnly)); } else { *pNumBytes = 0; *ppBytes = NULL; } }