Flash Media Live Encoder 3.2 / FAQ
- Before starting and initialization
- Devices and connection to Adobe Media Server
- Authentication and encoding session
- Subscriber and saved file
Before starting and initialization
- What are the minimum system requirements for Adobe® Flash® Media Live Encoder 3.2?
- Refer to the system requirements or the ReadMe file file included in the product.
- What happens if the encoding computer does not meet the minimum system requirements?
- If the encoding computer does not meet the minimum system requirements, the resulting audio/video stream might be compromised. Always make sure that CPU usage does not exceed 75% while encoding, or the quality of the encoded file could be affected.
- The Preview window is blank. What should I do?
- Make sure the audio/video capture device is working and is properly connected to the system/capture card.
- On the right side of the Flash Media Live Encoder interface, next to Preview, verify that the Input Video, Output Video, and Audio checkboxes are selected.
- Check for any error messages on the Encoding Log tab.
- Try using a different video device.
- Update the drivers of the device.
- Why is the video preview flickering?
- Check the graphics card on the encoding computer; it should be overlay enabled or should support Video Mixing Renderer (VMR).
- Why can't I see the crop selection in the video input preview window?
- Check the graphics card on the encoding computer; it should be overlay enabled or should support VMR.
- Why am I getting limited frame rate values?
- This may happen for IEEE 1394 devices because they populate the value field based on the video standard. The value is 29.97fps for NTSC and 25fps for PAL.
- Why is the Device Timecode option disabled?
- This option is disabled when either the device is not capable of providing the timecode or the device timecode DLL is missing from the Timecode folder in the application installation directory. However, you may use the System Timecode option to embed the system time as a timecode in the video stream or file.
- Why is Deinterlace disabled?
- Deinterlace works only for video sizes that have a height greater than or equal to 480 pixels and a width greater than or equal to 576 pixels.
Devices and connection to Adobe Media Server
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- What capture devices are supported by Flash Media Live Encoder?
- All DirectShow supported devices that give data in raw format can be used with Flash Media Live Encoder. See the list of capture devices certified for Flash Media Live Encoder.
- Why is my capture device not listed in the device drop-down list?
- Verify that the device is listed in the Device Manager and the device drivers are properly installed. Also, make sure that the device supports DirectShow.
- I am getting an error message that states "Device in use." What should I do?
- First, make sure no other application is using the device. Then, try the following:
- Exit Flash Media Live Encoder.
- Exit the device.
- Restart Flash Media Live Encoder and ensure the Video and Audio checkboxes in the Encoding Options panel are selected. Flash Media Live Encoder searches for a compatible device. Your device should then appear in the Device list.
- Does the application tamper with the audio and video timestamps in the workflow?
- In general, Flash Media Live Encoder does not tamper with the audio or video timestamps. But when the device gives video frames with a backward timestamp, those frames are dropped. With audio, if the samples have a backward timestamp, then the timestamp value is adjusted.
- I am getting a "Format not supported" error. What formats are supported?
- Flash Media Live Encoder supports only raw data from video and audio devices. The supported raw video formats include I420, YV12, YUY2, UYVY, RGB24, and RGB32.
- Why do I get an error message that states "Combination of frame rate and video size is not supported"?
- The device may not support the combination of frame rate and video size that you selected. Change either the frame rate or the video size.
- Why do I get the warning message that states "The selected audio device doesn't allow setting volume intensity, disabling the volume slider control"?
- This error occurs when the audio device filter does not expose the interface required to set the audio intensity. The volume level will be the default level sent by the device.
- Why do I get an error that states "Encountered error while encoding after a long duration"?
- This error occurs when the device starts behaving unexpectedly (sending packets with wrong or backward timestamps) after a long encoding session. The application will restart itself after encountering this error. This error will not affect the video quality.
- What does the error message "Incorrect samples given by the device" mean?
- There could be two reasons for this error:
- The device is sending packets with negative or incorrect timestamps.
- The device is sending zero byte packets.
- What protocols are used by Flash Media Live Encoder to connect to Adobe Media Server?
- Flash Media Live Encoder uses RTMP and RTMPT to connect to the server.
- Why can't I connect to Adobe Media Server?
- Verify that the encoding computer is connected to the network. Also, verify that the connection URL to Adobe Media Server is correct and that the Adobe Media Server application to which you're connecting exists. Make sure that the port on the server is enabled and the firewall is not blocking the connection. Also make sure that the Allow tag in vhost.xml in Adobe Media Server contains the correct parameters. Refer to the vhost.xml for the correct parameters.
- Will Flash Media Live Encoder reconnect to my server if the server goes offline for some reason?
- Yes. Flash Media Live Encoder tries to reconnect every five seconds (by default) until a connection is established. However, you can change that default setting and determine how often and for how long Flash Media Live Encoder tries to reconnect by editing the profile file. Refer to Flash Media Live Encoder Help for more details.
- I am getting an error stating "Invalid stream name." What should I do?
- Verify that the stream name is not already used by that application. Also, make sure the stream name follows stream-naming conventions for Adobe Media Server.
- How can I determine Flash Media Live Encoder version information at the server?
- Flash Media Live Encoder version information is passed as a user agent ID to the server.
- Does Flash Media Live Encoder resolve the hostname and cache the IP address for subsequent connections?
- Hostname resolution occurs at every reconnection attempt. Flash Media Live Encoder does not cache the IP address of the server.
Authentication and encoding session
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- How can I enable authentication on Adobe Media Server?
- Download the Authentication add-in and install it on Adobe Media Server.
- Why does the credential log-in window appear multiple times in a single encoding session?
- Credentials are saved only for each connect-disconnect session and not for a complete encoding session.
- Do I need to have separate credentials for different applications on the server?
- No. Default authentication is implemented at the server level, not at the application level. If desired, you can implement a custom server-side access module for application-level authentication.
- Why do I get a different bitrate than what I selected?
- The selected bitrate represents the average value at which the application should encode; the actual bit rate depends primarily on the content. Complex video sequences require more bits compared to still video. Also, if there is a drop in frame rate, either due to the device or high CPU usage, the actual bitrate will differ.
- Why do I get a different frame rate than what I selected?
- The selected frame rate represents the average value at which the application should encode; the actual frame rate depends on the frame rate the application is getting from the device. Some devices do not give the video at the desired frame rate. It may be lower or higher. Also, in the Encoding Statistics panel on the Encoding Log tab, check for frame drops. If there are frame drops, make sure CPU usage of the system is not more than 75%.
- Flash Media Live Encoder is dropping too many video frames. What should I do?
- Make sure the CPU usage of the encoding computer does not exceed 75%. If it does, try increasing the video bitrate or decreasing the video size or frame rate.
- Why is the virtual memory usage of Flash Media Live Encoder increasing?
- Verify the buffer value from the Flash Media Live Encoder publishing statistics. If this value is high, then network conditions are unfavorable, and Flash Media Live Encoder is unable to stream the data to the server. If the buffer value keeps increasing, then Flash Media Live Encoder may crash. Use Auto Adjust to overcome this issue.
- What is the maximum bandwidth I can stream to the server in optimal network conditions?
- By default, you can stream up to 20Mbps of data to the server.
- Why can I still see interlaced video even with Deinterlacing turned on?
- The deinterlace filter is based on a simple vertical blur algorithm and is not very effective at higher video sizes. Adobe suggests that you deinterlace at the hardware level for better quality and performance.
- What video bitrate value should I use?
- Select a bitrate according to the video content. For large and dynamic video input, you need a higher bitrate. An extremely low bitrate might result in low-quality video and pixilation. For small and relatively still video input, you can use a lower bitrate.
- Which H.264 profile and level should I use?
- The Base profile uses less CPU power than the Main profile but compromises video quality. If you want high-quality video and you have a good hardware configuration system, use the Main profile; otherwise the encoder might reduce the output fps during the encoding process.
H.264 levels define the limit on the combination of video size, frame rate, and bitrate that the encoder can encode. Changing the H.264 level does not have any impact on video quality and CPU usage. For details, see the Flash Media Live Encoder Help and Wikipedia article on H.264. - What audio encoding settings should I use?
- Adobe recommends you use the highest available sample rate to get the best quality. The bit rates listed below are only suggestions; actual bit rates vary from case to case.
For music, movies, and mixed content, try the following bit rates:
For speech, dialogue, and meeting content, use the same ranges listed above, but use Mono for the channel setting.Bitrate Audio format Channel Less than 48kbps HE-AAC Parametric stereo 48–96kbps HE-AAC Stereo 80–160kbps MP3 Stereo 128–224kbps AAC Stereo Above 224kbps MP3 or AAC Stereo (for MP3) or LC stereo (for AAC)
Subscriber and saved file
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- I am getting poor-quality audio. What should I do?
- Make sure that the CPU usage is not above 75% on the computer running Flash Media Live Encoder and on the subscriber computer.
- The buffer length on the subscriber computer should be a non-zero value.
- If the distortions are periodic, reduce the sampling rate.
- Make sure that the capture device is sending good-quality audio.
- The video playback is stalling. What should I do?
- Verify that the source is sending video frames without stalling.
- Try increasing the input frame rate. Lower fps video is not as smooth as higher fps video.
- Verify the output frame rate in the Statistics panel on the Encoding Log tab.
- Make sure that there are no frame drops at the encoder level.
- Try reducing the sample rate of the audio or encode only video. If the video quality improves, try switching to a different audio device.
- Determine whether Auto Adjust with the Drop Frames option is enabled. If Auto Adjust with the Drop Frames option is enabled, the video will stall at the subscriber end.
- If the stalling is present only in the live stream and not in the local file, adverse network conditions, such as high latency and bandwidth congestion, might cause the video to stall. Try using Auto Adjust with the Degrade Quality option.
- Video quality is poor; there is pixelation in the video. How can I improve the video?
- Pixelation occurs when the video bitrate is not sufficient to encode the video. Increasing the video bitrate will usually resolve the issue. Also, if you are using the H.264 base profile, try switching to the Main profile.
- What should I do when audio and video are out of sync in the subscribed stream?
- Open a new subscriber and verify that the problem occurs.
- Ensure that the CPU usage of the encoding computer and the subscriber computer is not more than 75%.
- Ensure that the buffer length of the subscriber is a non-zero value.
- A low frame rate can create a perception that video and audio are out of sync. Try encoding at a higher frame rate.
- There is latency in the published stream at the subscriber end. What should I do?
- Ensure that the CPU usage of the encoding computer and the subscriber computer is not more than 75%.
- Verify that the buffer length at the subscriber end is not higher than the set value.
- Try changing the video codec. the Adobe Flash Player runtime buffers 64 frames to play H.264 content.
- Try reducing the frame rate or bitrate. The encoder requires a high processing time for higher video settings, which can result in latency.
- Try using the Auto Adjust feature because adverse network conditions can result in latency.
- The buffer length at the subscriber end is increasing. What can I do?
- Ensure that the CPU usage of the encoding computer and the subscriber computer is not more than 75%.
- Try switching to video-only encoding. The audio device may be sending more audio samples than expected. If so, change the audio device.
- Try switching to audio-only encoding. The video device may be sending frames that have forward timestamps. If so, change the video device.
- What Auto Adjust settings should I use?
- Auto Adjust is used to adjust video settings dynamically in case of adverse network conditions between Flash Media Live Encoder and Adobe Media Server. With Auto Adjust, you can select either the Drop Frames or the Degrade Quality option. Drop Frames will drop video frames at the RTMP end, and Degrade Quality will reduce the bitrate of the encoded stream. The Degrade Quality option affects both the primary and backup stream as well as the file that is being saved. The Drop Frames option adjusts each stream individually. The saved file will not be affected.
- Why is my subscriber's buffer periodically emptying?
- This problem occurs because of adverse network conditions. Try reducing the bitrate to work better with the network bandwidth, or try the Auto Adjust feature.
- Why am I getting jittery video?
- Jittery video occurs if the subscriber buffer empties. Change the buffer size of the subscriber to a non-zero value.
- What is the recommended buffer value at the subscriber end?
- The size of the buffer depends on two factors:
- Desired latency: The larger the buffer, the longer it takes for the stream to start.
- Stream stability: Larger buffers allow the stream to deal with noise and interruptions better on the network. Making the buffer bigger increases the chance that the stream will play through without any stutters, gaps, or other interruptions.
Live applications that use the Live Aggregate Messages feature on Adobe Media Server to improve performance need to use a buffer that is at least as long as the delay introduced by the live aggregation. The delay is 500ms (0.5s) by default but can be configured on a per-application basis. If the buffer isn't long enough, the stream will not play back smoothly.
For dynamic bitrate switching, Adobe recommends using a buffer length value that is equal to the keyframe frequency of the encoded video. - Why can't I play my saved file?
- Per the MP4 standard, Flash Media Live Encoder creates fragmented F4V files that are optimized for streaming from Flash Media Server. F4V or MP4 playback applications that do not fully conform to the MP4 specification may fail to play.
If the Flash Media Live Encoder process is terminated during encoding, the saved file will be closed improperly and will not be playable.
