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Audio/Video Encoding Overview

supported audio and video formats on Roku devices

Overview

It is important to understand the available encoding methods and supported formats when streaming content on Roku devices. The following information will give you a good basis and help you choose the best options for distributing content based on quality and availability.

Roku officially supports the following media formats:

  • Video file types: MP4, MOV, M4V, MKV, WebM
  • Video codecs: H.264/AVC, HEVC/H.265, VP9
  • Audio file types: AAC, MP3, WMA, WAV (PCM), AIFF, FLAC, ALAC, AC3, EAC3
  • Streaming protocols: HLS, Smooth, DASH

These have been tested and/or are currently in-use. Other formats or encodings may be supported, but should be evaluated on a case by case basis.

Sections:

Streaming Protocols

Because network speeds can vary over time, a crucial aspect when providing the best experience to your viewers is providing multiple video streams of varying quality. Roku devices can then automatically select the best streaming quality based on the viewer's network connection.

Roku supports the following widely-used standard formats for adaptive bit rate switching:

  • HLS (HTTP Live Streaming)
  • Smooth Streaming
  • DASH (Dynamic Adaptive Streaming over HTTP)

Live Streaming / Live Video

Roku supports live video streaming in the following formats:

  • HLS
  • Smooth Streaming

Supported Video Formats

Roku devices support the following file types:

  • MP4
  • MOV
  • M4V
  • MKV
  • WebM1

Videos can be encoded using H.264, HEVC (H.265), or VP9 codecs.

H.264 HEVC (H.265)1 VP91
Aspect Ratio2 Various Various Various
Dimension Various up to 1920x1080 Various up to 3840x2160 Various up to 3840x2160
Video File Format .mp4, .mov, .m4v, .mkv .mp4, .mov, .m4v, .mkv .webm, .mkv
Streaming Format HLS: .m3u8, .ts
Smooth: .ismc
DASH: .dash		 HLS: .m3u8, .ts
Smooth: .ismc
DASH: .dash		 DASH: .dash
Input Frame Rate 3 24p, 30p, 60p 24p, 30p, 60p 24p, 30p
Color Space YUV YUV and YUV 10-bit YUV
Profile Main/High Main 10 Profile 0
Level/Complexity 4.0 5.1 5
Video Mode Constrained VBR Constrained VBR Constrained VBR
Average Streaming Video Bit rate Up to 10Mbps Up to 40Mbps Up to 40Mbps
Average USB Video Bit rate 384Kbps – 10Mbps Up to 40Mbps Up to 40Mbps
Peak Video Bit rate 1.5x average 1.5x average 1.5x average
Key Frame Interval 4 < 10s < 10s < 10s
DRM PlayReady for Smooth/DASH

Streaming AES-128 bit encryption for HLS		 PlayReady for Smooth/DASH

Streaming AES-128 bit encryption for HLS		 PlayReady for DASH

Widevine Level 1

Device Specific Features

Roku 4K capable devices All other Roku devices
TEE5 Yes No
HDCP 2.2 1.4

1 Only supported on Roku 4K capable devices.

2 The dimensions vary on a title-by-title basis depending on the source material and the target aspect ratio for the encoding (such as 4:3 or 16:9). Content should always be encoded at full width, and the height is adjusted. For example, a 1.66 aspect ratio source is encoded as a 720x432 video and displayed as letterboxed for a 4:3 display.

3 The frame rate used for encoding depends on the source material. Film content is generally 23.976 FPS, while video content is generally at 29.97.

4 All segments should start with an IDR frame and align across all bit rate variants. The recommended segment size is < 10 seconds for VOD and < 5 seconds for live content, and the segment size should be constant.

5 Trusted Execution Environment

Supported Audio Formats

Roku devices support the following audio file types:

  • AAC: HE-AACv2, AAC-LC (CBR)
  • MP3
  • WMA, WAV (PCM)
  • AIFF
  • FLAC
  • ALAC
  • Passthrough: Dolby Digital (AC3), Dolby Digital Plus (EAC3), DTS
AAC1 AC3/EAC32 DTS
Decode/Passthrough Decode Passthrough Passthrough
Sampling Rate 44.1 Khz, 48 Khz As supported by sink device As supported by sink device
Sample Size 16-bit As supported by sink device As supported by sink device
Bit rate 32-256 Kbps As supported by sink device As supported by sink device
Number of Channels 2.0 As supported by sink device As supported by sink device

1 Multichannel AAC is not supported on all Roku models. Roku TV’s and Roku 4 set-top-boxes support multichannel decode to PCM stereo.

2 Roku TVs can decode AC3 and EAC3 to PCM stereo.

Best Practices

For typical streaming video applications, we recommend a range of about 800Kbps to about 4.0Mbps. For USB playback, we recommend that you stay under 8.0 Mbps. This provides a good balance between quality and support for a wide number of users. In some cases, lower and higher bit rates have been used, but this frequently results in a bad quality, or limits the numbers of users that can view those encodings.

Lowest and Highest bit rates:

  • Roku recommends encoding a low bit rate stream around 800Kbps.
  • Roku recommends the user have at least a 1.5Mbps connection.
  • Some customers will have low bit rate connections around 1Mbps or experience intermittent network load that causes drops below Roku recommended network speeds.

4K UHD Video Streaming Recommendations

The following are recommendations for streaming 2160p video content (available on Roku 4 and Roku 4K TV devices).

Supported Profiles:

  • ISO Base Media File Format and VOD only.

Signaling:

  • DASH is the preferred adaptive streaming format with HEVC as the preferred video codec.
  • The recommended bit rates are 8, 10, 15, and 20Mbps.
  • All recommended bit rates should be in the same DASH stream.
  • Supported audio formats include AAC, AC3, and EAC3.
  • AAC 2-channel stereo should be provided as an alternate audio track to surround sound.

Segment Size and Alignment:

  • All encoded segments must start with an IDR frame.
  • The recommended adaptive streaming segment sizes are 2.5, 3.3, or 5 seconds.
  • The segment sizes should be constant and the same for all bit rates for the best adaptive switching and trick play (with 10 second BIF files).

Encryption:

  • Only PlayReady encryption is supported.