Function whip_write_packet

libavformat/whip.c:2039–2136

}

static int whip_write_packet(AVFormatContext *s, AVPacket *pkt)
{
    int ret;
    WHIPContext *whip = s->priv_data;
    AVStream *st = s->streams[pkt->stream_index];
    AVFormatContext *rtp_ctx = st->priv_data;
    int64_t now = av_gettime_relative();
    /**
     * Refer to RFC 7675
     * Periodically send Consent Freshness STUN Binding Request
     */
    if (now - whip->whip_last_consent_tx_time > WHIP_ICE_CONSENT_CHECK_INTERVAL * WHIP_US_PER_MS) {
        int size;
        ret = ice_create_request(s, whip->buf, sizeof(whip->buf), &size);
        if (ret < 0) {
            av_log(whip, AV_LOG_ERROR, "Failed to create STUN binding request, size=%d\n", size);
            goto end;
        }
        ret = ffurl_write(whip->udp, whip->buf, size);
        if (ret < 0) {
            av_log(whip, AV_LOG_ERROR, "Failed to send STUN binding request, size=%d\n", size);
            goto end;
        }
        whip->whip_last_consent_tx_time = now;
        av_log(whip, AV_LOG_DEBUG, "Consent Freshness check sent\n");
    }

    /**
     * Receive packets from the server such as ICE binding requests, DTLS messages,
     * and RTCP like PLI requests, then respond to them.
     */
    ret = ffurl_read(whip->udp, whip->buf, sizeof(whip->buf));
    if (ret < 0) {
        if (ret == AVERROR(EAGAIN))
            goto write_packet;
        av_log(whip, AV_LOG_ERROR, "Failed to read from UDP socket\n");
        goto end;
    }
    if (!ret) {
        av_log(whip, AV_LOG_ERROR, "Receive EOF from UDP socket\n");
        goto end;
    }
    if (ice_is_binding_response(whip->buf, ret)) {
        whip->whip_last_consent_rx_time = av_gettime_relative();
        av_log(whip, AV_LOG_DEBUG, "Consent Freshness check received\n");
    }
    if (is_dtls_packet(whip->buf, ret)) {
        if ((ret = ffurl_write(whip->dtls_uc, whip->buf, ret)) < 0) {
            av_log(whip, AV_LOG_ERROR, "Failed to handle DTLS message\n");
            goto end;
        }
    }
    if (media_is_rtcp(whip->buf, ret)) {
        uint8_t fmt = whip->buf[0] & 0x1f;
        uint8_t pt = whip->buf[1];
        /**
         * Handle RTCP NACK packet
         * Refer to RFC 4585 6.2.1