Possible To Get BBC R3 In FLAC using GiP?
C E Macfarlane
c.e.macfarlane at macfh.co.uk
Thu Aug 3 04:38:53 PDT 2017
Thanks Vangelis for a very complete explanation ... Further points below ...
--
www.macfh.co.uk/MacFH.html
> -----Original Message-----
> From: get_iplayer [mailto:get_iplayer-bounces at lists.infradead.org]On
> Behalf Of Vangelis forthnet
> Sent: 03 August 2017 00:13
> To: get_iplayer at lists.infradead.org
> Subject: Re: Possible To Get BBC R3 In FLAC using GiP?
>
> On Wed Aug 2 18:43:49 BST 2017, C E Macfarlane wrote:
>
> > if it is possible to obtain the Proms iPlayer streams in FLAC,
>
> Hello Charles, I do hope all's well with you!
Thanks, not too bad, and you I hope.
> The BBC do not provide AOD in flac, hence
> it's impossible to acquire such files via GiP
> (which currently only supports on-demand streams).
> Recent Support Forum thread:
> https://squarepenguin.co.uk/forums/thread-1463-post-6518.html
Ah, a 'CEM standard'* W7 build I'm creating for my newer PCs already has a
recent version of VLC installed, I wonder if that might be able to download
the FLAC stream? I'll look into it.
* I use builds to my own standards on all my PCs, so that as far as possible
regardless of age they all have the same suite of programmes installed.
> > are only live broadcasts available as FLAC?
>
> Precisely :-) Do note that this feature is only a
> BBC Labs test; so it might not return after
> Proms season is over.
> There has been a relevant (albeit off-topic)
> list thread back in April
> http://lists.infradead.org/pipermail/get_iplayer/2017-April/01
> 0436.html
> when the experiment first went live, but TBH
> the choice of thread title isn't very
> indicative of the thread's subject (so as
> to spot it easily inside the list archives)... ;-(
Too right. No wonder I didn't find it! It was obviously a great mistake to
search each month's thread titles for something relevant, like 'flac' for
example :-)
> The live flac stream is using MPEG-DASH
> (unencrypted) type of delivery, the exact
> mpd (media presentation description) URI is:
>
> https://vs-dash-ww-rd-live.bbcfmt.hs.llnwd.net/al/lossless/cli
> ent_manifest.mpd
>
> (the -ww- part of the hostname, which belongs to
> a Limelight CDN, indicates the stream is not geo-blocked,
> so audiophiles from all over the world can test it,
> provided their OS+Firefox version support it).
>
> Back during the GiP 2.95-dev era (Jan 2016), the GiP coder
> briefly experimented with supporting live radio dash streams:
> https://github.com/get-iplayer/get_iplayer/commit/8a90279
> but this feature never made it to a released version:
> https://github.com/get-iplayer/get_iplayer/commit/9f6b8c6
>
> Probably someone else with the required perl (or other)
> expertise can conjure up a perl script to dump that live
> DASH (but FLAC encoded) stream to file.
>
> ===================================
> OT info (STOP HERE if bothered by OT content):
>
> FWIW, a special patch for FFmpeg that only applies
> to a special (previous) snapshot of FFmpeg
> (commit git-20f7872) has been posted here:
> https://patchwork.ffmpeg.org/patch/3346/
> (or http://ffmpeg.org/pipermail/ffmpeg-devel/2017-April/210141.html)
> but this initial DASH stream recording feature
> hasn't made it to the official repo yet...
>
> I have been successful in compiling a win32 FFmpeg build
> (FFmpeg-n3.4-dev-301-git-20170409-N-85396-g20f7872+dash_demuxe
> r_v14-libressl-win32)
> that is able to capture this flac LIVE stream, unfortunately
> it's a non-free build, as it uses libressl (openssl fork) as
> the crypto lib; notice the stream uses HTTPS...
>
> The RAW flac stream that is dumped to disk is not
> a proper flac file, rather a "fragmented" flac file, the
> product of dash streaming; so simply issuing
>
> ffmpeg -v 16 -stats -re -i
> "https://vs-dash-ww-rd-live.bbcfmt.hs.llnwd.net/al/lossless/cl
> ient_manifest.mpd"
> -t 00:30:00 -vn -c:a copy BBCR3LL.flac
>
> will produce a non-seekable file with many
> software players; better mux the stream to
> the OGG container:
>
> ffmpeg -v 16 -stats -re -i
> "https://vs-dash-ww-rd-live.bbcfmt.hs.llnwd.net/al/lossless/cl
> ient_manifest.mpd"
> -t 00:30:00 -vn -c:a copy BBCR3LL.oga
>
> or experimental mux to the MP4 container:
>
> ffmpeg -v 16 -stats -re -i
> "https://vs-dash-ww-rd-live.bbcfmt.hs.llnwd.net/al/lossless/cl
> ient_manifest.mpd"
> -t 00:30:00 -vn -c:a copy -strict -2 BBCR3LL_tmp.mp4
> ffmpeg -v 32 -stats -i BBCR3LL_temp.mp4 -vn -c:a copy -strict
> -2 -movflags
> faststart BBCR3LL.mp4 && del BBCR3LL_tmp.mp4
>
> for seekable files (needs recent versions of players);
> or losslessly recode on-the-fly to flac:
>
> ffmpeg -v 16 -stats -re -i
> "https://vs-dash-ww-rd-live.bbcfmt.hs.llnwd.net/al/lossless/cl
> ient_manifest.mpd"
> -t 00:30:00 -vn -c:a flac BBCR3LL-rc.flac
>
> BTW, if you plan to edit the recorded flac stream
> further with FFmpeg, you'll bump on this bug:
> https://trac.ffmpeg.org/ticket/4905
> You'll have to
> DECODE TO WAV => PIPE => EDIT => ENCODE TO FLAC
> E.g. to cut out a segment from an hour's worth
> of live stream, I used:
>
> ffmpeg -v 8 -stats -i original.flac -vn -f wav - | ffmpeg -v
> 8 -stats -i - -ss 00:42:19 -to 00:58:11 -vn -af
> aformat=s16:48000 cut.flac
>
> If you can't compile for yourself that
> special, DASH enabled, build of FFmpeg,
> then your best bet is to try a recent nightly
> build of VLC 3.0.0-git (win builds link):
>
> http://nightlies.videolan.org/build/win32/last/
>
> Often times, those nightly builds are unstable
> (might even cause BSODs), but nothing evil
> has happened to my system by running the latest
> compiles (e.g. I'm on VLC 3.0.0-git-20170731-0258).
> You'll have to tweak the GUI to make that red
> Record button appear (not there by default), then
> search on how to record a live stream with VLC;
> use the mpd URI posted previously...
> VLC 3.0.0-git muxes the segmented FLAC
> stream inside the OGG container by default,
> resulting in an .ogg file.
>
> MediaInfo log:
>
> Format : Ogg
> Format/Info : Free Lossless Audio Codec
> File size : 7.47 MiB
> Duration : 1 min 21 s
> Overall bit rate mode : Variable
> Overall bit rate : 772 kb/s
>
> Audio
> ID : 533993841 (0x1FD41971)
> Format : FLAC
> Format/Info : Free Lossless Audio Codec
> Muxing mode : pre-FLAC 1.1.1
> Duration : 1 min 21 s
> Bit rate mode : Variable
> Channel(s) : 2 channels
> Channel positions : Front: L R
> Sampling rate : 48.0 kHz
> Bit depth : 16 bits
>
> HOWEVER, any attempt to extract (demux) the RAW audio
> stream with FFmpeg (3.3.1) fails for me, unless I
> recode to flac:
>
> ffmpeg -v 16 -stats -i "vlc-record-2017-08-03-01h36m18s-Radio 3
> lossless-.ogg" -vn -c:a copy "Radio 3 lossless.flac" =>
>
> Could not write header for output file #0 (incorrect codec
> parameters ?):
> Invalid data found when processing input
> (a 0.00 Byte file is created).
>
> ffmpeg -v 8 -stats -i "vlc-record-2017-08-03-01h36m18s-Radio 3
> lossless-.ogg" -vn -c:a flac "Radio 3 lossless.flac"
>
> successfully produces a .flac file!
> (verbosity reduced to 8 to prevent voluminous console output,
> though...)
> ===================================
Thanks for all this technical info. I'll look into what I can do with it.
> Best regards to all from super hot Greece!
> (29 Celsius @ 02:00 am)
Although I'm very grateful, wtf are you wasting holiday time on the likes of
me?! Enjoy it while you can! Up here in Sutherland we've had rain every
day for about 10 days now, and at least 5 days more is forecast. The one
exception was yesterday when for a few brief hours the grass was rather less
wet, so I thought I'd better mow while I could, even though to get it done I
had to raise the blades for a higher, less intensive cut.
Thanks again, best wishes, and regards, Charles.
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