Amazon Elastic Transcoder | Format Support

Question 1

Can I pass metadata when creating a job?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 1

You have the option to attach up to 10 custom metadata key-value pairs to your Elastic Transcoder jobs. This metadata will be included in the job notifications and when reading the job via the API or console. You provide this information in the “UserMetadata” field on the Job object.

Question 2

What input formats do you support?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 2

We support popular web, consumer and professional media formats. Examples include 3GP, AAC, AVI, FLV, MP4 and MPEG-2. If there is a format that you’ve found does not work, please let us know through our forum.

Question 3

Where can I find a comprehensive list of support formats?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 3

We add new input formats on an ongoing basis, so such a list would age quickly. Please take advantage of our free tier and console to try a format not mentioned above and if you run into problems, please let us know!

Question 4

When creating MP4 files, do you support “fast start”?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 4

We locate the MOOV atom for an MP4 at the start of the file so that your player can start playback immediately without waiting for the entire file to finish downloading.

Question 5

Do you support Apple ProRes or digital cinematography formats?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 5

We do not support reading Apple ProRes files or raw camera formats like ARRI and RED at this time.

Question 6

What video formats can I transcode into?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 6

We support the following video codecs: H.264, VP9, VP8, MPEG-2, and animated GIF. File formats supported include MPEG-2 TS container (for HLS), fmp4 (for Smooth Streaming and MPEG-DASH), MP4, WebM, FLV, MPG, and MXF (XDCAM-compatible). For information on file formats that are supported by specific codecs, please visit the Product Details page.

Question 7

What audio formats can I transcode into?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 7

We support the following audio codecs: AAC, MP3, MP2, PCM, FLAC, and Vorbis. Audio-only file formats supported include MP3, MP4, FLAC, OGA, OGG, and WAV. For information on file formats that are supported by specific codecs, please visit the Product Details page.

Question 8

How is album art supported for audio files?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 8

Album art is supported in MP4 files containing AAC audio, in MP3 files, and in FLAC files. Album art is not supported for OGA, OGG, WAV, WebM or MPEG-2 TS outputs. You can specify whether album art from the source file is passed through to the output, removed, or whether new album art should replace it or be appended to it.

Question 9

How do I create an audio file from a video file?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 9

To strip out video and create an output that only contains the audio track, run a transcoding job with your input file and use one of the system transcoding presets that contains Audio in its name. Alternatively, you can create your own audio only custom transcoding preset. The output file will only contain the audio portion of the input file.

Question 10

Do you support surround sound formats?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 10

The audio portion of the transcoded output from Amazon Elastic Transcoder is two-channel AAC, MP3 or Vorbis.

Question 11

Do you support audio channel remapping?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 11

If the source file contains multi-channel audio, the output will contain the first two channels, which are frequently left and right audio tracks. For the MXF container, we support multiple modes of packaging the audio into the file, including optional insertion of motor only shots (MOS).

Question 12

Can I generate XDCAM-compatible video?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 12

Yes, the easiest way to generate XDCAM-compatible outputs is to specify one of the XDCAM system presets when creating a transcoding job. You can also create a custom preset by choosing the MXF container with MPEG-2 video and PCM audio.

Question 13

Do you support closed captions?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 13

Yes, you can add, remove, or preserve captions as you transcode your video from one format to another.

Supported input formats:

Embedded: CEA-608, CEA-708 (MPEG-2 only) and mov-text

Sidecar captions: DFXP, EBU-TT, SCC, SMPT, SRT, TTML, WebVTT

Supported output formats:

Embedded captions: mov-text (MP4), and CEA-708 (MP4 and MPEG-TS)

Sidecar captions: DFXP, EBU-TT, SCC, SMPT, SRT, TTML, and WebVTT

CEA-708 captions are embedded in the H.264 SEI user data of the stream.

Question 14

Can you support multiple caption tracks?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 14

Yes, you can add one track per language.

Question 15

How do I create content for HLS output?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 15

There are two steps:

Create a transcoding job containing outputs for each variation using one of our supplied system presets or your own, based on the MPEG-2 TS container and H.264 and AAC codecs. The lowest rate stream should be an audio only stream.

Specify that the transcoding job create a playlist that references the outputs. You should order your bit rates from lowest to highest, with the audio only stream last, since this order will be maintained in the generated playlist file. Once your transcoding job has completed, the output bucket will contain a proper arrangement of your master and individual M3U8 playlists, and MPEG-2 TS media stream fragments.

Note: When selecting the HLSv4 option, your outputs should be matched to audio-only and video-only presets. For system presets, these can be identified by words “Audio” or “Video” as part of their name. For example, “System preset: HLS Video – 600k,” would match with the HLSv4 option whereas “System preset: HLS – 600k,” would be used with the HLSv3 option.

Question 16

How do I create content for Smooth Streaming?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 16

There are two steps:

Create a transcoding job containing outputs for each variation using one of our supplied system presets or your own, based on the fragmented MP4 container and H.264 and AAC codecs.

Specify that the transcoding job create a playlist that references the outputs. Once your transcoding job has completed, the output bucket specified by the transcoding pipeline will contain your manifest ISM file, client ISMC file, and fragmented MP4 media files.

Question 17

How do I create content for MPEG-DASH streaming?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 17

There are two steps:

Create a transcoding job containing the video-only outputs (with the desired resolutions and bitrates) and the audio-only output using either the system presets or your own customized presets, based on the fragmented MP4 container with H.264 video and AAC audio.

Create an MPEG-DASH playlist for the transcoding job by selecting MPEG-DASH as the Playlist Format. Specify the outputs that this playlist will reference. Once your transcoding job has completed, the output bucket specified by the transcoding pipeline will contain your manifest MPD file, and the fragmented MP4 media files.

Question 18

Should I use the HLSv3 or the HLSv4 option?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 18

HLS version 3 has been supported natively on iOS 2+ devices since July 2008 and on Android 4.0+ since Oct. 2011. HLS version 4 has been supported natively on iOS 5+ devices since Oct. 2011 and on Android 4.4+ since Sept. 2013.

If you able to reach your target devices with HLS version 4, you will be able to generate playlists that use byte range requests, late-binding audio, and I-frame only playback. Playlists with byte range requests are able to use just one file per bit rate, eliminating the need to manage thousands of small segment files. Late-binding audio allows the audio to be streamed separately from the video, eliminating redundant audio storage. I-frame only playback enables trick-play modes used to enhance fast-forward, rewind, and seeking through the video.

Question 19

Can I stream HLS directly from S3?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 19

Yes, you can play your HLS renditions directly from S3 by pointing the player to the M3U8 playlist. We recommend you use a CDN such as Amazon CloudFront, which provides a better end user experience with improved scalability and performance. See Configuring On-Demand Apple HTTP Live Streaming (HLS).

Question 20

Do I need a streaming server to deliver my Smooth Streaming content?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 20

Usually playing back Smooth Streaming requires an IIS origin server, and you cannot stream directly from S3. However, if you distribute your content with CloudFront you can simply configure a CloudFront Smooth Streaming distribution, eliminating the need for a streaming server. See Configuring On-Demand Smooth Streaming.

Question 21

Why is the codec parameter that I want to change not exposed by the API?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 21

In designing Amazon Elastic Transcoder, we wanted to create a service that was simple to use. Therefore, we expose the most frequently used codec parameters. If there is a parameter that you require, please let us know by letting us know through our forum.

Question 22

What settings do I use to preserve the dimensions of my video?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 22

Use the following settings in your custom preset:

MaxWidth: auto; MaxHeight: auto; SizingPolicy: ShrinkToFit; PaddingPolicy: NoPad; DisplayAspectRatio: auto

Question 23

How do I scale my output to a specified width and set the height to preserve the aspect ratio of the source content?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 23

Use the following settings in your custom preset:

MaxWidth: [Desired Width]; MaxHeight: auto; SizingPolicy: Fit; PaddingPolicy: NoPad; DisplayAspectRatio: auto

Question 24

How do I limit the height or width of a video without stretching the output to fit my set limit while preserving the input aspect ratio?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 24

Use the following settings in your custom preset:

MaxWidth: [Desired Width Limit]; MaxHeight: [Desired Height Limit]; SizingPolicy: ShrinkToFit; PaddingPolicy: NoPad; DisplayAspectRatio: auto

Question 25

What settings should I use to create a preset that causes the output video to fill the screen without distortion, if necessary cropping some of the edges (“center cut”)?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 25

Use the following settings in your custom preset:

MaxWidth: [Desired Width]; MaxHeight: [Desired Height]; SizingPolicy: Fill; PaddingPolicy: NoPad; DisplayAspectRatio: auto

Question 26

What settings should I use to create a preset that causes the output video to fill the screen without cropping any image area, if necessary distorting the image (“squeeze” or “stretch”)?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 26

Use the following settings in your custom preset:

MaxWidth: [Desired Width]; MaxHeight: [Desired Height]; SizingPolicy: Stretch; PaddingPolicy: NoPad; DisplayAspectRatio: auto

Question 27

How do I make my watermark scale with my video?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 27

In the watermark settings of your transcoding preset, set the HorizontalAlign, VerticalAlign, and Target parameters as desired. Then set the HorizontalOffset and VerticalOffset with relative parameters. For example, to place the watermark 10% away from the edges, set both values to 10%.

Question 28

How do I avoid distorting my watermark?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 28

If you do not want your watermark to be distorted when the video output is resized, set the SizingPolicy to ShrinkToFit while setting MaxWidth and MaxHeight to 100%. With these settings, Elastic Transcoder will never up-sample, expand, or distort your watermark.

Question 29

What are the settings for placing my watermark over the active video region rather than over the matte?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 29

To place your watermark so that it is always over the active video content, use relative size for the MaxWidth and MaxHeight settings, and set the Target to be Content. For example, to fix the watermark size to 10% of the active output video size, set both MaxWidth and MaxHeight to 10%.

Question 30

How do I use multiple watermarks?

Format Support

Amazon Elastic Transcoder | Media Services

Answer 30

Presets specify placement settings for up to four watermarks. Each setting has an associated watermark ID. You can create a job with up to four watermarks by specifying an array of watermarks in the job creation call. Each element of the array specifies the Id of the watermark setting to use, and the watermark image file.