developer documentation r17362

Creating custom transcoder profiles

The Media Factory transcoder will create a few standard files such as thumbnails, a Flash video file, and standard image sizes file for every video, audio and image that is uploaded. For most cases, these files are all you need to put an application together, but there may be times when you require custom files.

Setting up custom transcoder profiles allows you specify additional image sizes, video codecs and bitrates or audio formats. For example, you may want small, 16x9 thumbnails and high-quality H.264 video.

Create New Image Profile

Create a new profile by selecting Media Transcoder in the Media Manager sub menu, and then click New...

• Title: Descriptive name of the profile.
• Export format: The type of file to be created. In the case of my 16x9 thumb example, I am creating JPEGs.
• Apply to filetypes: Select the types of media from which the thumbs should be created. In this example, I want both images and videos to have 16x9 thumbs.
• Auto-convert: There may be cases where only a few files will need this profile applied. Selecting this box ensures that for every uploaded file (from now on), this file will be created.

After you click Create, the profile details page is displayed.

Additional options:

• Resizing method: Select how the image size and dimensions are handled. In this example, I want my 16x9 thumbs to be absolute size, with no distortion, so I selected Crop.
• Resample: A good choice when you intend to resize incoming images by a large factor.
• Width: The maximum width of the new file in pixels
• Height: The maximum height of the new file in pixels
• Quality: Select the compression / quality setting. 100 is beautiful,large files, where 10 is ugly, tiny files.

Create New Video Profile

Create a new profile by selecting Media Transcoder in the Media Manager sub menu, and then click New...

In this example, I will choose to create a profile for high quality video, called H.264 HQ

Additional options:

• Resizing method: Select how the video size and dimensions are handled. In this example, I want prevent 16x9 videos and 4x3 videos from being stretched or squashed, so I selected Preserve aspect ratio.
• Width: The maximum width of the new file in pixels
• Height: The maximum height of the new file in pixels
• Retain original quality: Checking this box will automatically determine the optimal bitrate to retain the same quality as the original. This can result in very large files. This is usually reserved for sending created files to a broadcast system.
• Maximum video bitrate: This is the filesize to quality ratio. 300 is low quality, small file. 1000 is typically a high-quality, larger file. For this example, I will choose 700, a good balance.
• Video framerate: 15fps is typical for web video, 29.97 is the NTSC broadcast standard. For my high-quality videos, I am using 30fps.
• Deinterlace video: Many videos are interlaced, and look bad on the web. Unless you know you are uploading progressive videos, check this box.
• 2-pass encoding: Generates a higher-quality video, but takes longer to create. This is NOT compatible with H.264, so I am leaving it unchecked. We recommend two-pass encoding for FLV, however.
• Export audio: No check, no sound.
• Audio bitrate: Save on bitrate by selecting lower rates for simpler audio, such as dialogue. 128 is the default.
• Audio sampling rate: Only change this if you are creating 8khz 3GP (mobile) video profiles.
• Audio channels: Only change this if you are creating mono 3GP (mobile) video profiles.

Accessing the Files

For how to access the files via templates and the API, start here.

To access the files in Media Factory, visit the Embed Options via the Media Detail page.

Under available sizes, the default files as well as the custom files are listed. You can click any of the links to preview the media. Unless the profile is set to automatically generate the file, you will see a button to create it. It will be added to the transcoder queue. When complete, the custom image or video will appear in place, or via a link.