TV Audio Bitrates
richard22j at zoho.com
Fri Aug 25 16:04:32 PDT 2017
On 25/08/2017 16:28, Vangelis forthnet wrote:
>But still the "Not so" part of his post stands true for various pids
>outside the main BBC TV channels...
> Just try (with 3.02)
> get_iplayer --type=tv --pid=p059b38x --tvmode=hvfsd
> (pid expires in 2 days) and you'll discover it fetches as a 128kbps hvf*
> mode... One other oddity for this pid is it's not available as legacy
> hls* (/flash*) tvmodes, only dvf*/hvf*.
> I guess a better choice of wording would be:
> "GiP 3.02 tries to download every hvf* tvmode with a 320kbps audio
> stream, whenever that one is available on the CDN server"
> Notice I didn't say "when it's available by the BBC", because the BBC do
> not officialy and publicly make such a stream available via their
> iPlayer interface.
> It was a code hack first implemented by youtube-dl devs (Python) and
> then ported to GiP (perl) and fine-tuned afterwards that allows for
> 320kbps audio streams inside hvf* tv files...
As you say, this example is outside the main BBC channels, and more
specifically not a regular broadcast. I am sure you have done more
analysis than I, but to a large extent regular broadcasts have PIDs
beginning with b and special programmes such as Red Button or clips have
PIDs beginning with p. In the case of Red Button programmes there is
usually no HLS mode. I think this is the first time I have seen a
125kbit/s audio rate for a TV programme but that may be because when
there has been no HLS mode I have usually used HVFxsd rather than a
50fps mode. That up to now has given 96kbit/s HE-AAC v1 in contrast to
96kbit/s AAC-LC for HLShd. The video also has some unfamiliar settings.
When you say "available on the CDN server" are you saying that different
CDNs have different audio? In any event a nice feature would be for
--info to display audio settings. As far as I am aware the iPlayer only
offers a single audio stream, unlike satellite broadcast.
This programme was not in my cache and --info in v3.02 could not find
it, but I was nevertheless able to download it.
As for temperatures, I read today that in south-east England it had been
the coldest August for 30 years. If you can spare any of your heat it
would be very welcome!
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