int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length, void *logctx, int is_nalff, int nal_length_size, enum AVCodecID codec_id) { int consumed, ret = 0; const uint8_t *next_avc = buf + (is_nalff ? 0 : length); pkt->nb_nals = 0; while (length >= 4) { H2645NAL *nal; int extract_length = 0; int skip_trailing_zeros = 1; /* * Only parse an AVC1 length field if one is expected at the current * buffer position. There are unfortunately streams with multiple * NAL units covered by the length field. Those NAL units are delimited * by Annex B start code prefixes. ff_h2645_extract_rbsp() detects it * correctly and consumes only the first NAL unit. The additional NAL * units are handled here in the Annex B parsing code. */ if (buf == next_avc) { int i; for (i = 0; i < nal_length_size; i++) extract_length = (extract_length << 8) | buf[i]; if (extract_length > length) { av_log(logctx, AV_LOG_ERROR, "Invalid NAL unit size (%d > %d).\n", extract_length, length); return AVERROR_INVALIDDATA; } buf += nal_length_size; length -= nal_length_size; // keep track of the next AVC1 length field next_avc = buf + extract_length; } else { /* * expected to return immediately except for streams with mixed * NAL unit coding */ int buf_index = find_next_start_code(buf, next_avc); buf += buf_index; length -= buf_index; /* * break if an AVC1 length field is expected at the current buffer * position */ if (buf == next_avc) continue; if (length > 0) { extract_length = length; } else if (pkt->nb_nals == 0) { av_log(logctx, AV_LOG_ERROR, "No NAL unit found\n"); return AVERROR_INVALIDDATA; } else { break; } } if (pkt->nals_allocated < pkt->nb_nals + 1) { int new_size = pkt->nals_allocated + 1; H2645NAL *tmp = av_realloc_array(pkt->nals, new_size, sizeof(*tmp)); if (!tmp) return AVERROR(ENOMEM); pkt->nals = tmp; memset(pkt->nals + pkt->nals_allocated, 0, (new_size - pkt->nals_allocated) * sizeof(*tmp)); pkt->nals_allocated = new_size; } nal = &pkt->nals[pkt->nb_nals++]; consumed = ff_h2645_extract_rbsp(buf, extract_length, nal); if (consumed < 0) return consumed; /* see commit 3566042a0 */ if (consumed < length - 3 && buf[consumed] == 0x00 && buf[consumed + 1] == 0x00 && buf[consumed + 2] == 0x01 && buf[consumed + 3] == 0xE0) skip_trailing_zeros = 0; nal->size_bits = get_bit_length(nal, skip_trailing_zeros); ret = init_get_bits(&nal->gb, nal->data, nal->size_bits); if (ret < 0) return ret; if (codec_id == AV_CODEC_ID_HEVC) ret = hevc_parse_nal_header(nal, logctx); else ret = h264_parse_nal_header(nal, logctx); if (ret <= 0) { if (ret < 0) { av_log(logctx, AV_LOG_ERROR, "Invalid NAL unit %d, skipping.\n", nal->type); } pkt->nb_nals--; } buf += consumed; length -= consumed; } return 0; }