qvidiumQVidium Encoder/Decoder Troubleshooter

 

Video Transmission Problems

            (Transmission from QVENC or QVPRO Encoder to QVDEC Decoder)

·        No Video

1.      Click on Network/Ping on Encoder and try to ping decoder

§  If ping fails, check network connectivity

2.      Check Status on Encoder. Do you see a non-zero output stream bitrate? If Yes, go to 3.

Ø  If bitrate is zero or blank, check for a valid video source or that the correct input has been selected.

Ø  For SDI input, make certain that it has embedded audio

Ø  For HD-SDI without embedded audio, enable “Use Analog Audio for HD Video” under Advanced Profile

Ø  On a QVPRO for HDMI input, make certain that you see a green HDMI Lock light on the front of the codec. If it is off, then the codec cannot sync to the HDMI source.

Ø  Check the video source resolution. The QVPro and QVENC can only encode the following input video resolutions: 1080p, 1080i, 720p, 576i, and 480i. You must insure that the input is one of these formats for encoding to start.

3.      Check status on Decoder. For a zero bitrate:

Ø  If there is a firewall, check that the video UDP port is forwarded to the codec. The default UDP video port is 10000.

4.      If the incoming bitrate at the decoder is zero (0):

Ø  Please remember that to send video over the Internet, you cannot use the local 192.168.XXX.YYY address. Any IP address beginning with 192 is a private address, and cannot be directly used over the public Internet. Most Internet connections are through a Firewall. You must set up Port Forwarding, or Network Address Translation (NAT) so that when you send the video stream from your encoder, you can use the public IP address of the firewall, and have the firewall forward those packets to the decoder. Please see your network administrator for further help in setting up your firewall to enable port forwarding to the decoder.

Ø  If you are using ARQ error correction, we suggest that you set the ARQ port and the video UDP port to the same value (if you are not using server mode) so that you can avoid setting up port forwarding for the ARQ retransmission request packets on the encoder-side firewall.

5.      If the decoder shows a non-zero network bitrate, then check that you are using the correct video output. HDMI ONLY outputs HD video. Composite ONLY outputs SD video. (SDI can output either SD or HD video.)

·        Video Freezes/Pauses

1.      Check Status on Decoder. Is the Network Packet Loss non-zero?

Ø  If you have packet loss, then make certain that the IP Transport is set to ARQ on both the encoder and decoder.

Ø  If ARQ Recovered is always zero, yet the number of Unrecovered (or Not Recovered) packets is non-zero, then the upstream ARQ retransmission request packets are not getting out of the decoder and into the encoder. By default, the UDP port for both the downstream video and upstream ARQ retransmission request packets is 10000.

Ø  If both the ARQ Recovered and Unrecovered/Not Recovered are non-zero, then try increasing the ARQ Target Latency. The number of retries should be 3 or greater in this case. Increasing the Target Latency will add delay, but also increase the number of retry attempts to recover lost packets.

Ø  If the Unrecovered/Not Recovered packet losses continue to increment each time you click on Status (or when the page refreshed when on Monitor), then you may be overloading your Internet connection. Try:

Ø        1) Reducing the Stream Bit Rate on the encoder, and

Ø        2) Setting the Use Bandwidth Ceiling under the Advanced Networking tab on the Encoder Profile to YES.

Ø  You can also try setting the Stream Mode to Capped VBR instead of Constant Bit Rate under Advanced Encoding to reduce network loading.

Ø  If you continue to have video freezing, then click on Decoder/Show Log and mail that to support@qvidium.com. If that log has entries that warn of Break in PCR or Audio Buffer Underflow, then your network connection to the Internet, either upstream from the encoder or downstream to the decoder, may be experiencing interruptions of several seconds or more that the ARQ error correction cannot fix. In this case, please contact your Internet Service Provider (ISP) to check for problems in the service or routing. You may want to subscribe to MPLS (Multi-Protocol Labeled Switching) service to give you a better and fixed Internet connection from the encoder to the decoder. You can click on Network/Traceroute or Network/Ping to check on the connectivity from the encoder to the decoder and vice versa. If the traceroute shows multiple IP addresses at one or more of the network hops, then your ISP is using Dynamic Load Balancing on your connection which may be causing the interruptions. Getting MPLS Service can eliminate this problem.

2.      If there is no packet loss, or minimal packet loss:

Ø  Click on Encode/Show Log.

Ø  If you are using SDI input and see SDI Lost Lock messages, then please check the SDI input. You may need to replace the SDI coax cable and/or use a shorter cable. You can also consider using a re-clocking SDI Distribution Amp to clean up your SDI signal going to the encoder.

·        Video Color Distortion

1.      If using SDI or HDMI input, try enabling Resync SDI or Resync HDMI, respectively, under Advanced Profile settings and restart encoder.

2.      Has the video source been previously encoded with a 4:2:0 encoder? If so, then successive encoding and decoding will degrade the color or result in "grainy" or fuzzy video.

3.      If the "Video Buffer Size" parameter on the decoder is too small, the decoder can lose sync for certain types of video content, resulting in black and white video or video with severe color distortion. To remedy this, please try increasing the "Video Buffer Size" on the decoder to 500 ms, save the new setting and restart the decoder.

4.      If problem persists, check video source.

·        Other Video Distortion, Blurriness, or Pixelation

Ø  Try increasing video bitrate on encoder.

Ø  Insufficient encoding bitrate can cause blurrier video, pixelation of the image for high-motion content.

·        Low Latency Mode: Minimizing End-to-End Delay

Ø  Set the following parameters on encoder:

Ø  On Basic Encoder Profiles: Set IP Transport to  UDP.

Ø  On Advanced Encoder Profiles, set Stream Mode to Low Delay.

Ø  Set the following parameters on decoder:

Ø  On Video Decoder Profile: Set Video buffer size to 80 ms (if the video is choppy, then increase this value).

Ø  On Network Decoder Profiles: Set IP Transport to UDP.

Ø  If the video occasionally gets into a low frame rate mode, then under Advanced Encoding, set the B frames to 1 and P frames to 2. If this fixes the issue, you can then try increasing the P frame value to improve video quality..