int ff_hevc_extract_rbsp(HEVCContext *s, const uint8_t *src, int length, HEVCNAL *nal) { int i, si, di; uint8_t *dst; if (s) nal->skipped_bytes = 0; #define STARTCODE_TEST \ if (i + 2 < length && src[i + 1] == 0 && src[i + 2] <= 3) { \ if (src[i + 2] != 3) { \ /* startcode, so we must be past the end */ \ length = i; \ } \ break; \ } #if HAVE_FAST_UNALIGNED #define FIND_FIRST_ZERO \ if (i > 0 && !src[i]) \ i--; \ while (src[i]) \ i++ #if HAVE_FAST_64BIT for (i = 0; i + 1 < length; i += 9) { if (!((~AV_RN64A(src + i) & (AV_RN64A(src + i) - 0x0100010001000101ULL)) & 0x8000800080008080ULL)) continue; FIND_FIRST_ZERO; STARTCODE_TEST; i -= 7; } #else for (i = 0; i + 1 < length; i += 5) { if (!((~AV_RN32A(src + i) & (AV_RN32A(src + i) - 0x01000101U)) & 0x80008080U)) continue; FIND_FIRST_ZERO; STARTCODE_TEST; i -= 3; } #endif /* HAVE_FAST_64BIT */ #else for (i = 0; i + 1 < length; i += 2) { if (src[i]) continue; if (i > 0 && src[i - 1] == 0) i--; STARTCODE_TEST; } #endif /* HAVE_FAST_UNALIGNED */ if (i >= length - 1) { // no escaped 0 nal->data = nal->raw_data = src; nal->size = nal->raw_size = length; return length; } av_fast_malloc(&nal->rbsp_buffer, &nal->rbsp_buffer_size, length + AV_INPUT_BUFFER_PADDING_SIZE); if (!nal->rbsp_buffer) return AVERROR(ENOMEM); dst = nal->rbsp_buffer; memcpy(dst, src, i); si = di = i; while (si + 2 < length) { // remove escapes (very rare 1:2^22) if (src[si + 2] > 3) { dst[di++] = src[si++]; dst[di++] = src[si++]; } else if (src[si] == 0 && src[si + 1] == 0) { if (src[si + 2] == 3) { // escape dst[di++] = 0; dst[di++] = 0; si += 3; if (s && nal->skipped_bytes_pos) { nal->skipped_bytes++; if (nal->skipped_bytes_pos_size < nal->skipped_bytes) { nal->skipped_bytes_pos_size *= 2; av_assert0(nal->skipped_bytes_pos_size >= nal->skipped_bytes); av_reallocp_array(&nal->skipped_bytes_pos, nal->skipped_bytes_pos_size, sizeof(*nal->skipped_bytes_pos)); if (!nal->skipped_bytes_pos) { nal->skipped_bytes_pos_size = 0; return AVERROR(ENOMEM); } } if (nal->skipped_bytes_pos) nal->skipped_bytes_pos[nal->skipped_bytes-1] = di - 1; } continue; } else // next start code goto nsc; } dst[di++] = src[si++]; } while (si < length) dst[di++] = src[si++]; nsc: memset(dst + di, 0, AV_INPUT_BUFFER_PADDING_SIZE); nal->data = dst; nal->size = di; nal->raw_data = src; nal->raw_size = si; return si; }