Possible To Get BBC R3 In FLAC using GiP?
CJB
chrisjbrady at gmail.com
Fri Aug 4 01:15:44 PDT 2017
More techie info. here:
http://mudcat.org/thread.cfm?threadid=161901
CJB
On 03/08/2017, C E Macfarlane <c.e.macfarlane at macfh.co.uk> wrote:
> 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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