MPEG-DASH / Media Source demo

Decoder test media

This page is outdated. Before MSE was ready, we provided these samples for partners to test their implementations with. Now that MSE is widely deployed, and expectations on smooth decoder transitions are more broadly known, we don't expect them to be of much use. But in case they are...

This media exists to validate a decoder and video pipeline. It features H.264 video encoded at different sample rates and resolutions. Playback pipelines that can play these streams smoothly are ready for Media Source.

A compatible video pipeline must be able to decode each 30-second sequence without pauses, black frames, or improper frame ordering, dropping no more than two frames while the output pipeline is flushed and reconfigured. The dropped frames must not alter the timing of the audio track, and the audio and video tracks must be in sync again within one second after a change in frame size.

A fully-compliant video pipeline should not drop frames, and should deliver frames to the output device at a consistent 24 FPS. It should also initialize any resamplers in such a way that content is not unnecessarily scaled if input and output sizes match.

Checking audio/video sync: The audio track emits a 40ms tone which begins at one second intervals starting at t=0. This corresponds to the duration of the frames in which the two "spinners" are aligned (every 24th frame for the 24FPS examples, starting with the first frame).

Checking no unneeded rescaling: There is a small image feature at the 1px scale in 1920x1080 videos in the center of the "spinners". On implementations that do not perform unneeded rescaling, these should be fully resolved at the end of the 480p-720p-1080p test when rendering to a 1920x1080 target.

Background bitrate: The "background" samples feature a background which is very challenging to encode. The average bitrate of these segments is well above the stated maximum average bitrate as a result of single-pass encoding. This is an exceptional case, but it is possible that some media will trigger similar rate decisions, and so clients should decoding at these rates without issues.

Plain

Plain, no sound

Background

Background, no sound

Reference source: A high-bitrate version of the "background" video is here. This reference video has a near-BluRay bitrate, and implementations are not required to play it back smoothly.