User`s manual

User’s Manual v.13 QVidium

H.264 HD Video Codecs™

Technologies, Inc. Page 27 of 67

Encoder Operation

(QVENC and QVPRO Only)

This section explains how to operate the Codec as a video encoder. Once the encoder has started,

you can also change the audio attenuation and gain settings and dynamically change the video

encoding bitrate.

4.1

Starting and Stopping the Encoder

Enter http://IPAddress where IPAddress is the IP address of the encoder.

1. Select the Encoder menu on the left side of the web page.

2. Click the Start menu option underneath the Encoder menu. With only a single profile, the

encoder should now start. If you have more than one profile, then double-click on the desired

profile to start the encoder.

3. To confirm that the encoder has started, click on Status and confirm that the Bitrate is non-

zero. If you have trouble starting the encoder, please check that the appropriate link light for

the input you are using is on at the front of the codec. If not, then check your source. For SDI,

please check that the red error LED at the back of the codec is off. For HD-SDI, 3G-SDI,

and ASI inputs, please check that the appropriate green LED at the back of the codec is lit.

4. If these indicators look ok, then click on Show Log to check the log file. Near the end of that

page you should see the line, “Start encoding OK”. If the video source is absent or

invalid, the last line of the log may read: “Video NOT locked: waiting for valid

input”.

Note: To comply with copyright laws, the codec will not encode HDMI input with encryption.

Also, the HDMI input cannot currently handle SD video, only HD resolutions.

5. Likewise, click on Stop to stop the encoder. If the encoder is running, you can edit the

parameters and click on Start to restart the encoder with the new parameters. There is no

need to first stop the encoder since the Start command first performs a Stop operation.

Note: If you wish to reconfigure the encoder, remember to first Save any configuration changes

before restarting the encoder.

4.2

Dynamically Changing the Video Encoding Bitrate

Once encoding has begun, you can instantaneously vary the video encoding bitrate. This can be

useful when connecting to wireless modems and other network connections with limited, but

unpredictable, time-varying throughput characteristics. As described in this section, we provide

several mechanisms for dynamically adjusting the video encoding bitrate. In particular, this can

allow a modem to feed back link throughput constraints directly to the encoder to dynamically

optimize video quality over such bandwidth-constrained networking links.

Note: At present, this feature is only supported for VBR (variable bit rate) streams.