static int vp9_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_vp9_ctx, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags) { int has_pic_id, has_layer_idc, has_ref_idc, has_ss_data, has_su_data; av_unused int pic_id = 0, non_key_frame = 0; av_unused int layer_temporal = -1, layer_spatial = -1, layer_quality = -1; int ref_fields = 0, has_ref_field_ext_pic_id = 0; int first_fragment, last_fragment; int rtp_m; int res = 0; /* drop data of previous packets in case of non-continuous (lossy) packet stream */ if (rtp_vp9_ctx->buf && rtp_vp9_ctx->timestamp != *timestamp) ffio_free_dyn_buf(&rtp_vp9_ctx->buf); /* sanity check for size of input packet: 1 byte payload at least */ if (len < RTP_VP9_DESC_REQUIRED_SIZE + 1) { av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet, got %d bytes\n", len); return AVERROR_INVALIDDATA; } /* * decode the required VP9 payload descriptor according to section 4.2 of the spec.: * * 0 1 2 3 4 5 6 7 * +-+-+-+-+-+-+-+-+ * |I|L|F|B|E|V|U|-| (REQUIRED) * +-+-+-+-+-+-+-+-+ * * I: PictureID present * L: Layer indices present * F: Reference indices present * B: Start of VP9 frame * E: End of picture * V: Scalability Structure (SS) present * U: Scalability Structure Update (SU) present */ has_pic_id = !!(buf[0] & 0x80); has_layer_idc = !!(buf[0] & 0x40); has_ref_idc = !!(buf[0] & 0x20); first_fragment = !!(buf[0] & 0x10); last_fragment = !!(buf[0] & 0x08); has_ss_data = !!(buf[0] & 0x04); has_su_data = !!(buf[0] & 0x02); rtp_m = !!(flags & RTP_FLAG_MARKER); /* sanity check for markers: B should always be equal to the RTP M marker */ if (last_fragment != rtp_m) { av_log(ctx, AV_LOG_ERROR, "Invalid combination of B and M marker (%d != %d)\n", last_fragment, rtp_m); return AVERROR_INVALIDDATA; } /* pass the extensions field */ buf += RTP_VP9_DESC_REQUIRED_SIZE; len -= RTP_VP9_DESC_REQUIRED_SIZE; /* * decode the 1-byte/2-byte picture ID: * * 0 1 2 3 4 5 6 7 * +-+-+-+-+-+-+-+-+ * I: |M|PICTURE ID | (RECOMMENDED) * +-+-+-+-+-+-+-+-+ * M: | EXTENDED PID | (RECOMMENDED) * +-+-+-+-+-+-+-+-+ * * M: The most significant bit of the first octet is an extension flag. * PictureID: 8 or 16 bits including the M bit. */ if (has_pic_id) { if (len < 1) { av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); return AVERROR_INVALIDDATA; } /* check for 1-byte or 2-byte picture index */ if (buf[0] & 0x80) { if (len < 2) { av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); return AVERROR_INVALIDDATA; } pic_id = AV_RB16(buf) & 0x7fff; buf += 2; len -= 2; } else { pic_id = buf[0] & 0x7f; buf++; len--; } } /* * decode layer indices * * 0 1 2 3 4 5 6 7 * +-+-+-+-+-+-+-+-+ * L: | T | S | Q | R | (CONDITIONALLY RECOMMENDED) * +-+-+-+-+-+-+-+-+ * * T, S and Q are 2-bit indices for temporal, spatial, and quality layers. * If "F" is set in the initial octet, R is 2 bits representing the number * of reference fields this frame refers to. */ if (has_layer_idc) { if (len < 1) { av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); return AVERROR_INVALIDDATA; } layer_temporal = buf[0] & 0xC0; layer_spatial = buf[0] & 0x30; layer_quality = buf[0] & 0x0C; if (has_ref_idc) { ref_fields = buf[0] & 0x03; if (ref_fields) non_key_frame = 1; } buf++; len--; } /* * decode the reference fields * * 0 1 2 3 4 5 6 7 * +-+-+-+-+-+-+-+-+ -\ * F: | PID |X| RS| RQ| (OPTIONAL) . * +-+-+-+-+-+-+-+-+ . - R times * X: | EXTENDED PID | (OPTIONAL) . * +-+-+-+-+-+-+-+-+ -/ * * PID: The relative Picture ID referred to by this frame. * RS and RQ: The spatial and quality layer IDs. * X: 1 if this layer index has an extended relative Picture ID. */ if (has_ref_idc) { while (ref_fields) { if (len < 1) { av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); return AVERROR_INVALIDDATA; } has_ref_field_ext_pic_id = buf[0] & 0x10; /* pass ref. field */ if (has_ref_field_ext_pic_id) { if (len < 2) { av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); return AVERROR_INVALIDDATA; } /* ignore ref. data */ buf += 2; len -= 2; } else { /* ignore ref. data */ buf++; len--; } ref_fields--; } } /* * decode the scalability structure (SS) * * 0 1 2 3 4 5 6 7 * +-+-+-+-+-+-+-+-+ * V: | PATTERN LENGTH| * +-+-+-+-+-+-+-+-+ -\ * | T | S | Q | R | (OPTIONAL) . * +-+-+-+-+-+-+-+-+ -\ . * | PID |X| RS| RQ| (OPTIONAL) . . - PAT. LEN. times * +-+-+-+-+-+-+-+-+ . - R times . * X: | EXTENDED PID | (OPTIONAL) . . * +-+-+-+-+-+-+-+-+ -/ -/ * * PID: The relative Picture ID referred to by this frame. * RS and RQ: The spatial and quality layer IDs. * X: 1 if this layer index has an extended relative Picture ID. */ if (has_ss_data) { avpriv_report_missing_feature(ctx, "VP9 scalability structure data"); return AVERROR(ENOSYS); } /* * decode the scalability update structure (SU) * * spec. is tbd */ if (has_su_data) { avpriv_report_missing_feature(ctx, "VP9 scalability update structure data"); return AVERROR(ENOSYS); } /* * decode the VP9 payload header * * spec. is tbd */ //XXX: implement when specified /* sanity check: 1 byte payload as minimum */ if (len < 1) { av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n"); return AVERROR_INVALIDDATA; } /* start frame buffering with new dynamic buffer */ if (!rtp_vp9_ctx->buf) { /* sanity check: a new frame should have started */ if (first_fragment) { res = avio_open_dyn_buf(&rtp_vp9_ctx->buf); if (res < 0) return res; /* update the timestamp in the frame packet with the one from the RTP packet */ rtp_vp9_ctx->timestamp = *timestamp; } else { /* frame not started yet, need more packets */ return AVERROR(EAGAIN); } } /* write the fragment to the dyn. buffer */ avio_write(rtp_vp9_ctx->buf, buf, len); /* do we need more fragments? */ if (!last_fragment) return AVERROR(EAGAIN); /* close frame buffering and create resulting A/V packet */ res = ff_rtp_finalize_packet(pkt, &rtp_vp9_ctx->buf, st->index); if (res < 0) return res; return 0; }