All posts by john

Apache, Encoding, HTML5

Making HTML5 AAC audio work

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Web authors may be leaping to use the simple media embedding that HTML5 offers them: but there is a problem generated by the strictness of Microsoft’s Internet Explorer 9. It is particularly fussy, far more so than Google Chrome, about the mime-type of the media file.

As an example, a web page that includes this code:

<audio src="http://johnwarburton.net/aria.mp4" controls="true">

won’t play on Internet Explorer 9 when the file is served by an off-the-shelf Apache server running on Red Hat or Centos. The expected audio controls are replaced by a red cross. However, IE9 has the tools to analyse the problem (and, for that matter, so does Google Chrome, though the audio played first time). By pressing F12 and selecting the Console tab, one may query the Document Object Model for the error held by the audio object:

document.getElementsByTagName("audio")[0].error.code

One may need to adjust the index following ‘audio’ if the tag in question is not the first <audio> tag on the page. The error codes returned mean this:

  • MEDIA_ERR_ABORTED : 1
    The fetching process for the media resource was aborted by the user.
  • MEDIA_ERR_DECODE : 3
    An error has occurred in the decoding of the media resource, after the resource was established to be usable.
  • MEDIA_ERR_NETWORK : 2
    A network error has caused the user agent to stop fetching the media resource, after the resource was established to be usable
  • MEDIA_ERR_SRC_NOT_SUPPORTED : 4
    The media resource specified by the ‘src’ parameter was not usable.
The stock Apache server on Red Hat or Centos generates error 4 on an mp4 AAC audio file, and further investigation, again entirely within Internet Explorer 9, reveals the problem to be the server not sending the mime-type header which IE9 expects. Other browsers look at the file itself, but not IE9. Again, within the F12 debugging window, one may select the ‘Network’ tab, click the ‘Start Capture’ button, and reload the page to see the mime-types actually sent by the server. If the audio file doesn’t have type ‘audio/mp4’, the server’s mime-types file needs to be reconfigured to send it.
On the server, one needs to add this line to mime-types:
audio/mp4                       mp4

then restart the Apache server

service httpd restart

This cured the problem here.

Acknowledgement for this information is gladly given to the following blog from Microsoft: http://blogs.msdn.com/b/thebeebs/archive/2011/07/20/html5-video-not-working-in-ie9-some-tips-to-debug.aspx

 

Journalism, Legislation

Fit to print?

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Love it or hate it, the Daily Mail has a huge readership both in print and on its website. So aware of its worldwide audience is the Mail that its website, when viewed within the United States of America, produces a whole new tranche of sensationalist, audience-winning and, yes, cleverly-written stories aimed specifically at that country’s population. One need only take a short hop across the border to Canada to type the same address in one’s browser, then to be greeted once more by the familiar UK front page.

Paul Dacre, the editor-in-chief of the Daily Mail, spoke passionately on Wednesday morning about the progress of press reporting standards in the UK, and also awakened the spectre of a straitjacketed press should Parliament vote for compulsory press regulation:

News, let me remind you, is often something that someone – the rich, the powerful, the privileged – doesn’t want printed…. Indeed, I would argue that Britain’s commercially viable free press – because it is in hock to nobody – is the only really free media in this country. Over regulate that press and you put democracy itself in peril.

Paul Dacre’s speech is on-line here, at The Guardian’s website.

Film-making

Privacy in a Public Place: “Droit d’image”?

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Often, I’ve heard it said that the general public, while going about their daily lives in a public place, can have no expectation of privacy from filming, particularly if a documentary programme is being shot around them. However, a new ruling by Ofcom, the UK’s broadcasting regulator, has upheld a complaint of intrusion of privacy made by a worker, filmed in a public place, who asked a programme maker not to include his footage; and yet it was still shown.

The full ruling is here (search for ‘David Gemmell’ in the text). It would be sensible for film-makers to take the greatest care to keep records of requests made by their subjects, whether featured or not, and to abide by commitments made in correspondence with them.

Note that this was not a case of a consent/clearance form not being obtained: it was a particular objection to broadcast, which the programme-maker stated, in writing, would be respected. This ruling, also, does not raise the spectre of UK regulations mirroring the French concept of droit d’image which is shared by some other jurisdictions.