Generating report with mp4 video doesn't allow video to play in served report

Describe the bug Upon generating a report that include a video attached to a test, the served Allure report does not allow the mp4 video to be played

To Reproduce Steps to reproduce the behavior: Attached video with the following code snippet (Python):

        with open(os.path.join(VIDEO_RECORDINGS_DIR, _video_name), "rb") as video_file:
            allure.attach(video_file.read(), name="video", attachment_type=allure.attachment_type.MP4)

Attached generated Allure results dir - mp4 video is included and plays successfully independently and the report recognises that the there is a video attached to a test, but the video cannot be played

Expected behavior Video in report plays as when playing the video independently as a separate file in a media player.

Screenshots

Environment (please complete the following information):

| Allure version | 2.14.0 | | Test framework | pytest@6.2.4 | | Allure adaptor | allure-pytest@2.9.43 | | Generate report using | allure@2.14.0 |

Additional context Attached generated allure results dir with all artefacts: sample-allure.zip

[fescobar]

@jsa34 great!

[jsa34]

Interesting - I hadn’t considered the video type…

MP4 doesn’t work, but I swapped out the mp4 to be webm, and all is fine - only code change from Allure’s side is:

        with open(os.path.join(VIDEO_RECORDINGS_DIR, _video_name), "rb") as video_file:
            allure.attach(video_file.read(), name="video", attachment_type=allure.attachment_type.WEBM)

Obviously also rendered the video with vp09 codec (webm) instead of mp4, but no other changes - mp4 and webm videos both were playing fine outside of Allure report, even the video in the results dir