Parse avcC (AVC Decoder Configuration Record) at given offset. ISO 14496-15 section 5.2.4.1
| 44 | // Parse avcC (AVC Decoder Configuration Record) at given offset. |
| 45 | // ISO 14496-15 section 5.2.4.1 |
| 46 | bool parseAvcC(fl::span<const fl::u8> data, fl::size offset, fl::size boxEnd, |
| 47 | Mp4TrackInfo& info) { |
| 48 | // avcC box: 8 bytes header, then: |
| 49 | // u8 configVersion (1) |
| 50 | // u8 profile_idc |
| 51 | // u8 profile_compat |
| 52 | // u8 level_idc |
| 53 | // u8 lengthSizeMinusOne (& 0x03) |
| 54 | // u8 numSPS (& 0x1F) |
| 55 | // for each SPS: u16 spsLength, u8[] spsData |
| 56 | // u8 numPPS |
| 57 | // for each PPS: u16 ppsLength, u8[] ppsData |
| 58 | |
| 59 | fl::size pos = offset + 8; // skip box header |
| 60 | if (pos + 6 > boxEnd) return false; |
| 61 | |
| 62 | fl::u8 configVersion = data[pos++]; |
| 63 | if (configVersion != 1) return false; |
| 64 | |
| 65 | info.profile = data[pos++]; |
| 66 | pos++; // profile_compat |
| 67 | info.level = data[pos++]; |
| 68 | info.lengthSizeMinusOne = data[pos++] & 0x03; |
| 69 | |
| 70 | fl::u8 numSPS = data[pos++] & 0x1F; |
| 71 | for (fl::u8 i = 0; i < numSPS; i++) { |
| 72 | bool ok = true; |
| 73 | fl::u16 spsLen = readU16BE(data, pos, ok); |
| 74 | if (!ok) return false; |
| 75 | pos += 2; |
| 76 | if (pos + spsLen > boxEnd) return false; |
| 77 | fl::vector<fl::u8> sps(spsLen); |
| 78 | for (fl::u16 j = 0; j < spsLen; j++) { |
| 79 | sps[j] = data[pos + j]; |
| 80 | } |
| 81 | info.sps.push_back(sps); |
| 82 | pos += spsLen; |
| 83 | } |
| 84 | |
| 85 | if (pos >= boxEnd) return false; |
| 86 | fl::u8 numPPS = data[pos++]; |
| 87 | for (fl::u8 i = 0; i < numPPS; i++) { |
| 88 | bool ok = true; |
| 89 | fl::u16 ppsLen = readU16BE(data, pos, ok); |
| 90 | if (!ok) return false; |
| 91 | pos += 2; |
| 92 | if (pos + ppsLen > boxEnd) return false; |
| 93 | fl::vector<fl::u8> pps(ppsLen); |
| 94 | for (fl::u16 j = 0; j < ppsLen; j++) { |
| 95 | pps[j] = data[pos + j]; |
| 96 | } |
| 97 | info.pps.push_back(pps); |
| 98 | pos += ppsLen; |
| 99 | } |
| 100 | |
| 101 | return true; |
| 102 | } |
| 103 |