The Pro Transcoding license option enhances the built-in transcoding capabilities to allow for fully customizable Transport Stream transcoding profiles supporting HD/SD and MPEG-2 and H.264/AVC codecs. The Pro Transcoding license is a great option for Cable/Telco IP playout applications that do not require decoding/re-encoding for cost efficiency. In such applications, files normally require consistent, matching properties (A/V codecs, bit rates, multiplex rates). The Pro Transcoding option makes it easy to prepare files in this way without requiring external transcoding software. Simply drag and drop upload using the default profile, or transcode to specific profiles in the user interface.
With the Pro Transcoding license enabled, the Transcoding section of Config → Content will display an additional feature to Edit custom profiles, and to enable Transcode On Import. When Transcode On Import is enabled, all imported files will be transcoded to the default profile upon import.
Managing Transcoding Profiles
To manage Transcoding Profiles, click Profile: Edit.
Setting Default Transcode Profile
The default selections will display as a green check in the corresponding SD and HD columns. Pro Transcoding allows for a separate default profile for SD sources and HD sources. For example, if you require SD sources imported to transcode to an SD profile, and HD sources to an HD profile preserving source resolution. Alternatively, if you require SD to be upconverted to HD, or HD to be downconverted to SD, select the same SD or HD profile to be the default for both SD and HD sources. The default profiles are used when Transcoding is enabled and non-transport stream files are imported (unless Transmux is enabled and a file is Transmuxable), or when any file is imported with the Transcode On Import option enabled. When manually triggering a transcode via the Content actions, the default selection will be the default profile for convenience. To set your default transcode profiles, click the gray check action in the corresponding SD and HD columns.
Delete, Copy, Edit, and Add Transcode Profiles
To delete an existing profile, click the delete action. There are non-deletable, non-editable factory presets for CableLabs SD/HD MPEG-2/H.264 that can be used directly, or can be copied for convenience to use as a baseline for customized profiles. To copy an existing profile, click the copy action. To edit an existing profile, click the edit action. To create a new profile, click the add action. In each of these cases, you will be presented with the Transcoding Profile form.
Choose the desired Transcode Profile settings. The Transcode Profile fields are as follows:
- Name: Enter a name for the transcode profile.
- Description: Enter a description for the transcode profile.
- Resolution: Choose the output video width and height (in pixels) that also defines the aspect ratio.
- Frame Rate: Choose an output frame rate in frames per second (fps).
- Scan Mode: Choose the scan mode of the output file that determines how video frames are stored. For MPEG-2 codec, either Interlaced (Bottom Field First or Top Field First) or Progressive. For H.264/AVC codec, either Macroblock-adaptive Frame/Field (MBAFF) or Progressive. Progressive mode stores frames instead of fields. Bottom Field First (BFF) mode stores frames as separate fields, with the bottom field first. Top Field First (TFF) mode stores frames as separate fields, with the upper field first. MBAFF allows for a combination of interlaced and progressive.
- Profile: The profile code that defines the specific video codec features and capabilities to be used.
- Level: The level code that specifies a set of constraints for a given profile, such as the maximum picture resolution, frame rate, and bit rate.
- Video Codec: Video codec specifies what encoding format will be used for video. The available options are MPEG-2 and H.264.
- Video Bitrate: The video bit rate correlates to the video quality of the transcoded file. Higher bitrates provide better quality at the expense of increased file sizes.
- GOP Size: Choose the number of frames to make up a Group of Pictures, that allows for transition points for starting and stopping within the file for virtual trimming. For broadcast applications, half of a second worth of frames based on the frame rate is recommended, such as 15 frames for 29.97 or 30fps.
- Audio Codec: Audio codec specifies what encoding format will be used for audio. The available options are MPEG-1 Layer II, AC-3, and AAC.
- Audio Bitrate: The audio bit rate correlates to the audio quality of the transcoded file. Higher bitrates provide better quality at the expense of increased file sizes.
- Audio Channels: Choose either stereo (2 channel) or mono (1 channel) audio.
- Audio Sampling Rate: Choose the audio sampling rate in Hertz (Hz).
- Audio Normalization: Choose the algorithm to be used for processing audio to change audio levels to the corresponding Audio Level setting. Algorithm options are Off (no processing), RMS (Root Mean Square – adjust audio so the overall RMS matches the level setting), Peak (adjust audio samples respectively so the Peak matches the level setting), EBU128 (adjust audio samples to achieve average loudness matching the level setting per the EBU R128 standard).
- Audio Level: Choose the desired audio level for the corresponding Audio Normalization processing algorithm in dBFS for RMS and Peak, and LUFS for EBU128.
- Mux Rate: Sets the constant Multiplex (MUX) rate for the transcoded Transport Stream file that defines the total data rate including video, audio, and transport packets. A good rule of thumb is to set the MUX rate less than 10% above the sum of the video and audio bit rates, but high enough to meet minimum requirements. The application will display a warning if the MUX rate is set too low.
- Program Number: Choose the Transport Stream Program Number. Normally the Program Number should be set to 1.
- PMT PID: Choose the Transport Stream Packet Identifier (PID) for the Program Map Table (PMT).
- PCR and Video PID: Choose the Transport Stream Packet Identifier (PID) for the Program Clock Reference (PCR) and Video.
- Audio PID: Choose the Transport Stream Packet Identifier (PID) for the Audio.
Click Save to save your changes.
Selecting a Transcode Profile When Transcoding
With the Pro Transcoding license option, you can manually transcode one or more files via the content transcode action with the ability to select which Transcode Profile to use.
Select the transcode profile to use from the list of available Transcode Profiles. Use Defaults will be the default selection that will use your SD and HD defaults depending on the source format.
The Tasks Tab will show the progress and status of each Transcode, and the details will show which Profile is used for the transcode.