static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags) { int start_partition, end_packet; int extended_bits, part_id; int pictureid_present = 0, tl0picidx_present = 0, tid_present = 0, keyidx_present = 0; int pictureid = -1, pictureid_mask = 0; int returned_old_frame = 0; uint32_t old_timestamp; if (!buf) { if (vp8->data) { int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); if (ret < 0) return ret; *timestamp = vp8->timestamp; if (vp8->sequence_dirty) pkt->flags |= AV_PKT_FLAG_CORRUPT; return 0; } return AVERROR(EAGAIN); } if (len < 1) return AVERROR_INVALIDDATA; extended_bits = buf[0] & 0x80; start_partition = buf[0] & 0x10; part_id = buf[0] & 0x0f; end_packet = flags & RTP_FLAG_MARKER; buf++; len--; if (extended_bits) { if (len < 1) return AVERROR_INVALIDDATA; pictureid_present = buf[0] & 0x80; tl0picidx_present = buf[0] & 0x40; tid_present = buf[0] & 0x20; keyidx_present = buf[0] & 0x10; buf++; len--; } if (pictureid_present) { if (len < 1) return AVERROR_INVALIDDATA; if (buf[0] & 0x80) { if (len < 2) return AVERROR_INVALIDDATA; pictureid = AV_RB16(buf) & 0x7fff; pictureid_mask = 0x7fff; buf += 2; len -= 2; } else { pictureid = buf[0] & 0x7f; pictureid_mask = 0x7f; buf++; len--; } } if (tl0picidx_present) { // Ignoring temporal level zero index buf++; len--; } if (tid_present || keyidx_present) { // Ignoring temporal layer index, layer sync bit and keyframe index buf++; len--; } if (len < 1) return AVERROR_INVALIDDATA; if (start_partition && part_id == 0 && len >= 3) { int res; int non_key = buf[0] & 0x01; if (!non_key) { vp8_free_buffer(vp8); // Keyframe, decoding ok again vp8->sequence_ok = 1; vp8->sequence_dirty = 0; vp8->got_keyframe = 1; } else { int can_continue = vp8->data && !vp8->is_keyframe && avio_tell(vp8->data) >= vp8->first_part_size; if (!vp8->sequence_ok) return AVERROR(EAGAIN); if (!vp8->got_keyframe) return vp8_broken_sequence(ctx, vp8, "Keyframe missing\n"); if (pictureid >= 0) { if (pictureid != ((vp8->prev_pictureid + 1) & pictureid_mask)) { return vp8_broken_sequence(ctx, vp8, "Missed a picture, sequence broken\n"); } else { if (vp8->data && !can_continue) return vp8_broken_sequence(ctx, vp8, "Missed a picture, sequence broken\n"); } } else { uint16_t expected_seq = vp8->prev_seq + 1; int16_t diff = seq - expected_seq; if (vp8->data) { // No picture id, so we can't know if missed packets // contained any new frames. If diff == 0, we did get // later packets from the same frame (matching timestamp), // so we know we didn't miss any frame. If diff == 1 and // we still have data (not flushed by the end of frame // marker), the single missed packet must have been part // of the same frame. if ((diff == 0 || diff == 1) && can_continue) { // Proceed with what we have } else { return vp8_broken_sequence(ctx, vp8, "Missed too much, sequence broken\n"); } } else { if (diff != 0) return vp8_broken_sequence(ctx, vp8, "Missed unknown data, sequence broken\n"); } } if (vp8->data) { vp8->sequence_dirty = 1; if (avio_tell(vp8->data) >= vp8->first_part_size) { int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); if (ret < 0) return ret; pkt->flags |= AV_PKT_FLAG_CORRUPT; returned_old_frame = 1; old_timestamp = vp8->timestamp; } else { // Shouldn't happen vp8_free_buffer(vp8); } } } vp8->first_part_size = (AV_RL16(&buf[1]) << 3 | buf[0] >> 5) + 3; if ((res = avio_open_dyn_buf(&vp8->data)) < 0) return res; vp8->timestamp = *timestamp; vp8->broken_frame = 0; vp8->prev_pictureid = pictureid; vp8->is_keyframe = !non_key; } else { uint16_t expected_seq = vp8->prev_seq + 1; if (!vp8->sequence_ok) return AVERROR(EAGAIN); if (vp8->timestamp != *timestamp) { // Missed the start of the new frame, sequence broken return vp8_broken_sequence(ctx, vp8, "Received no start marker; dropping frame\n"); } if (seq != expected_seq) { if (vp8->is_keyframe) { return vp8_broken_sequence(ctx, vp8, "Missed part of a keyframe, sequence broken\n"); } else if (vp8->data && avio_tell(vp8->data) >= vp8->first_part_size) { vp8->broken_frame = 1; vp8->sequence_dirty = 1; } else { return vp8_broken_sequence(ctx, vp8, "Missed part of the first partition, sequence broken\n"); } } } if (!vp8->data) return vp8_broken_sequence(ctx, vp8, "Received no start marker\n"); vp8->prev_seq = seq; if (!vp8->broken_frame) avio_write(vp8->data, buf, len); if (returned_old_frame) { *timestamp = old_timestamp; return end_packet ? 1 : 0; } if (end_packet) { int ret; ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index); if (ret < 0) return ret; if (vp8->sequence_dirty) pkt->flags |= AV_PKT_FLAG_CORRUPT; return 0; } return AVERROR(EAGAIN); }