Re: [gentoo-user] OT: what audio file format / container to play on Android.

[Mick]

On Friday 01 Jul 2016 15:52:49 Willie M wrote:
> On 07/01/2016 03:10 PM, Stroller wrote:
> > I've only recently started using my Android device for playing audio.
> >
> > About once a week I listen to a podcast, which is usually an MP3 I've
> > downloaded from NPR.org.
> >
> > On my laptop I copy these to Google Drive (big shout to net-misc/drive)
> > and then I can access then via Drive on my Android phone.
> >
> > Google Drive on Android seems to play these audio files on a built-in
> > player; its only controls are to skip forwards or backwards 30 seconds,
> > but this is adequate for podcasts.
> >
> > I have here a BBC radio show that I downloaded a couple of weeks ago with
> > net-misc/youtube-dl.
> >
> > When downloaded it saves as an .mp4 file. I have also tried renaming it to
> > .m4a but, either way, Google Drive complains "unable to process this
> > video".
> >
> > How do I need to process this audio to get it to play, please?
> >
> > I'd obviously prefer to keep the same audio stream, rather than
> > transcoding it. I assume that the player can handle AAC (??), it just
> > needs to be in another container.
> >
> > Thanks in advance for any suggestions,
> >
> > Stroller.
> >
> >
> >
> > Details:
> >
> >
> > $ youtube-dl http://www.bbc.co.uk/programmes/b07fl5bh
> > [bbc.co.uk] b07fl5bh: Downloading video page
> > [bbc.co.uk] b07fl2qw: Downloading media selection XML
> > [bbc.co.uk] b07fl2qw: Downloading m3u8 information
> > [bbc.co.uk] b07fl2qw: Downloading m3u8 information
> > [bbc.co.uk] b07fl2qw: Downloading m3u8 information
> > [hlsnative] Downloading m3u8 manifest
> > [hlsnative] Total fragments: 390
> > [download] Destination: The Bronze Age Collapse, In Our Time - BBC Radio
> > 4-b07fl2qw.mp4 [download] 100% of 40.56MiB in 01:42
> > [ffmpeg] Fixing malformated aac bitstream in "The Bronze Age Collapse, In
> > Our Time - BBC Radio 4-b07fl2qw.mp4" $ file The\ Bronze\ Age\ Collapse\,\
> > In\ Our\ Time\ -\ BBC\ Radio\ 4-b07fl2qw.mp4 The Bronze Age Collapse, In
> > Our Time - BBC Radio 4-b07fl2qw.mp4: ISO Media, MP4 Base Media v1 [IS0
> > 14496-12:2003] $ midentify The\ Bronze\ Age\ Collapse\,\ In\ Our\ Time\
> > -\ BBC\ Radio\ 4-b07fl2qw.mp4 ID_AUDIO_ID=0
> > ID_AID_0_LANG=eng
> > ID_CLIP_INFO_NAME0=major_brand
> > ID_CLIP_INFO_VALUE0=isom
> > ID_CLIP_INFO_NAME1=minor_version
> > ID_CLIP_INFO_VALUE1=512
> > ID_CLIP_INFO_NAME2=compatible_brands
> > ID_CLIP_INFO_VALUE2=isomiso2mp41
> > ID_CLIP_INFO_NAME3=encoder
> > ID_CLIP_INFO_VALUE3=Lavf56.25.101
> > ID_CLIP_INFO_N=4
> > ID_FILENAME=The\ Bronze\ Age\ Collapse,\ In\ Our\ Time\ -\ BBC\ Radio\
> > 4-b07fl2qw.mp4 ID_DEMUXER=lavfpref
> > ID_AUDIO_FORMAT=MP4A
> > ID_AUDIO_BITRATE=128000
> > ID_AUDIO_RATE=48000
> > ID_AUDIO_NCH=2
> > ID_START_TIME=0.00
> > ID_LENGTH=2495.91
> > ID_SEEKABLE=1
> > ID_CHAPTERS=0
> > ID_AUDIO_BITRATE=128000
> > ID_AUDIO_RATE=48000
> > ID_AUDIO_NCH=2
> > ID_AUDIO_CODEC=ffaac
> > ID_EXIT=EOF
> > $
>
> You can just have youtube-dl download just the audio of the youtube video.
>
> youtube-dl -x --audio-format mp3 http://www.bbc.co.uk/programmes/b07fl5bh
>
> You can also set other formats for the audio
>
> "best", "aac", "vorbis", "mp3", "m4a", "opus", or "wav"


Since the youtube-dl can only download the audio stream as suggested above, 
you don't need to transcode with ffmpeg - although it is not difficult to do so 
for streams you have already downloaded:

ffmpeg -i input.mp4 -q:a 0 -map a output.mp3

or output.m4a if you prefer.


As an alternative for BBC you could also use get_iplayer:

get_iplayer --get XXXX --radiomode=flashaachigh --
flvstreamer="/usr/bin/flvstreamer"

-- 
Regards,
Mick