This chapter shows you how to start an encoding job, and describes the different methods for monitoring a job. You will learn about encoding statistics, as well as the logging tool that displays errors and warnings about a job as it runs.
Once you have set up an encoding job, you can start and monitor the encoding process. The following procedure explains how to start and stop an encoding job.
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To start encoding a job: |
Music or Voice audio choice, and audiences, as described in Chapter 6.When you are finished encoding, click the Stop button. Or, if you have set a duration for the encode, you can wait until the duration is complete. Note that if you have defined multiple destinations, clicking Stop halts the encoding process for all destinations. You cannot stop the encoding process for one destination (such as writing to a clip) while continuing the process for another destination (such as broadcast to a server).
After the encoding process has finished, you can play a destination clip as long as you have RealPlayer installed on the RealProducer machine. To do this, choose File>Play RealMedia File (Ctrl+p), or click the RealPlayer play button below the destination window. Do not use this feature when encoding a live broadcast, however.
As you encode clips, you can monitor the audio levels for both the input audio and the encoded output audio. This helps to ensure that the audio levels are encoded in the optimal dynamic range. On an input or output audio meter, green for the left or right channel indicates a normal reading. Red warns that the audio is close to being over-modulated. If the audio registers above the possible dynamic range, the clipping indicator above the meter lights up to indicate that the audio has become distorted.
Optionally, you can disable the audio monitors. This helps to speed the encoding process, and is useful in live broadcasts in which you want to conserve as much processing power as possible. To turn off a meter, select View>Input Audio Meter, View>Output Audio Meter, or both. Selecting these options again reinstates the audio meters.
With RealProducer Plus, you can adjust the audio output using the Gain palette, which you can display with the Settings>Show Audio Gain Control (Ctrl+r) command. In this palette, you set a decibel gain from +12 (amplify the audio) to -12 (attenuate the audio). RealProducer saves the gain setting when you close the palette. The gain settings apply only to the current job.
When you amplify the audio signal, RealProducer dynamically compresses the
audio range if the output signal becomes overmodulated. Thus, the output
audio is never clipped, even at the maximum gain level. A value of 6 doubles
the audio level while a value of 12 quadruples it. A value of -6 reduces the level
to half, while -12 reduces it to a quarter.
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For More Information: Using a job file, you can specify a wider range. See "Audio Gain Prefilter". |
When the input audio has an audio gain that causes distortion, the clipping indicators above the input audio meter light up. In this case, RealProducer's gain control cannot eliminate the distortion. To eliminate the distortion, you may need to adjust the settings in your audio hardware or software that provides the audio input to RealProducer.
For example, the sound capture card may have its mixer levels set too high. In this case, adjust the analog gains leading to your sound card input so that the input audio meter on RealProducer never rises to the 0 dB level. If needed, modify audio gain through an external mixer board if the sound card's audio mixer does not provide adequate control.
With certain material and input sources, however, the external mixing may lead to sound levels that are too low on average. In this case, you can use the RealProducer gain control tool to bring the signal back up to acceptable levels. This is safe to do because the gain tool will not introduce clipping.
When your encoding job contains video, you will see the source video play in the input preview window. The output displays in the output preview window. Optionally, you can disable the input or output video windows. This helps to speed the encoding process by eliminating the need for RealProducer to display the video onscreen. This is useful in live broadcasts in which you want to conserve as much processing power as possible. To turn off a window, select View>Input Video, View>Output Video, or both. Selecting these options again reinstates the video display.
RealProducer displays a number of encoding statistics that you can monitor as you encode a clip or broadcast. These statistics provide an overview of the encoded output, showing you how well the encoding process meets your target settings. You can open the statistics window at any point before or during encoding by selecting View>Show Statistics (Ctrl+y). The job title appears at the top of the window.
RealProducer displays three different sets of statistics during three phases of the encoding process.
If you have configured an encoding job but not yet started it, the statistics window shows how the streams are configured. For a variable bit rate encoding (VBR), you'll see one audience. For a constant bit rate encoding (CBR), you'll see a separate line for each audience you've added. The statistics show the total bit rate for each stream, as well as the bit rates for the video and audio. They also show the maximum frames per second (FPS) for the video.
As you run an encoding job, the statistics window updates in real time to show how each stream is being encoded. Statistics do not display during the first pass of two-pass encoding, however.
When the encoding completes, the statistics window shows you the actual statistics for the entire encoding job. Some statistics, such as frames per second (FPS), are listed as averages.
The following table summarizes the encoding statistics that RealProducer displays. During the encoding, some statistics update in real-time. After the encoding, some fields display average values.
| Statistic | Description |
|---|---|
| Audience | Lists the audience template used to encode the stream. |
| Total Bit Rate | Indicates the total bit rate of the encoded audience stream, in the form of Kilobits per second (Kbps) with single decimal precision. If the rate is over 1 Megabit per second, the value is in Mbps with two decimal precision. |
| Video Bit Rate | Gives the bit rate of the video portion of the stream. If there is no video in the output, this displays as n/a. |
| Audio Bit Rate | Lists the bit rate of the audio portion of the stream. If there is no audio in the output, this displays as n/a. |
| FPS | Lists the video's frames per second. If encoding has not started, the value is the maximum target. During an encoding. the value is the actual fps being encoded. After the encoding, this field gives the average frame rate. For an audio-only clip, the value is n/a. |
| Min. FPS | Gives the minimum frame rate, in frames per second, encoded into the stream. For an audio-only clip, or before video encoding has started, the value is n/a. |
| Quality | Lists the quality level of the output compared to the input after all video filters have been applied. A value of 100 percent represents equivalent quality to the input. For an audio-only clip, or before video encoding has started, the value is n/a. See "Video Quality Index". |
| Min. Quality | Indicates the minimum quality level of the clip during encoding. For an audio-only clip, or before video encoding has started, the value is n/a. |
| Pre-roll | Lists the number of seconds of preroll (buffering) that the viewer will experience when beginning to play the encoded stream. |
The quality index indicates how well each RealVideo stream will play back:
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Tip: The purpose of SureStream substreams is to keep the presentation running during adverse network conditions. A poor quality level is therefore acceptable for these streams. |
RealProducer records messages about encoding tasks as they occur. Whereas the monitoring window provides statistics about the encoding job, the log file informs you about RealProducer performance, such as its CPU use. After a job has run, you can view the log files to find encoding errors or diagnostic messages. You can also use the log viewer to display encoding information on the screen in real-time, or after the job has finished.
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For More Information: The RealProducer preferences set the log file location and features, and determine how many messages display in the log viewer. See "Changing Log File and Log Viewer Preferences" for more information. |
The log viewer gives you a real-time view of the log messages as RealProducer generates them. It also provides the ability to filter the log to display just one type of message. Displaying the log viewer during encoding is particularly useful when you encode a live broadcast because the viewer can warn you about problems such as excess CPU consumption and lowered frame rates.
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To open the log viewer: |
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Tip: You can select and deselect the message types during encoding to update the log viewer output in real-time. |
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©2004 RealNetworks, Inc.
For more information, visit RealNetworks Click here if the Table of Contents frame is not visible at the left side of your screen. |
