Making seekable blob corrupts the video

[darind]

I have a webm video captured using Media Recorder API representing the current browser tab. In order to produce a seekable video I use the ts-ebml package like so:

ts-ebml -s input.webm | cat > input-seekable.webm

Most of the time this works pretty well, but I have noticed that with still videos (no moving frames), this produces corrupted video.

Here's an example of such input video:

input.webm.zip

After applying the seekable transformation on this input video I get the following corrupt video:

input-seekable.webm.zip

If you try opening the resulting video, playing it and then seeking towards the end, the playback stops.

Also if you open this video with some js player (such as shaka player) it throws the following error:

{
	"severity": 2,
	"category": 3,
	"code": 3016,
	"data": [3, null, "PIPELINE_ERROR_DECODE: {\"causes\":[],\"data\":{},\"stack\":[{\"file\":\"media/filters/vpx_video_decoder.cc\",\"line\":197}],\"status_code\":271,\"status_message\":\"\"}"],
	"handled": false
}