Home of the Squeezebox™ & Transporter® network music players.
Page 2 of 2 FirstFirst 12
Results 11 to 14 of 14
  1. #11
    I have noticed this as well with certain podcast feeds/streams.

  2. #12
    Member
    Join Date
    Apr 2005
    Location
    Wisbech, Uk
    Posts
    90
    Same here

  3. #13
    Senior Member
    Join Date
    Oct 2005
    Location
    Ireland
    Posts
    15,722
    Quote Originally Posted by dolodobendan View Post
    I downloaded this feed and here it's also 2455 seconds (40:55m).

    Episode overview in LMS: Duration reported as 2353s (39:13m)
    Episode duration reported while playing: 2509s (41:49m)

    Maybe it's nothing, but LMS reports a bitrate of 63 kbps CBR while VLC reports one of 64 kbps. I do remember some problems with badly encoded mp3s regarding duration and bitrate.
    All duration at teh start of playing an MP3 are estimates based on size and data rate of the file. I'm not sure but I think the data rate is not accurate (i.e. 64kbps will not be 64kbps for 100% of the file but should be the close to that figure for the whole file) it is really a max figure.

    To know exactly the duration of a file without playing it - convert to WAV as part of the conversion the real duration is saved in the header (e.g. lame --mp3input --decode --verbose input.mp3 output.wav ) - there is no compression so duration is accurate.

    LMS treats MP3 podcasts as streams so some values such as compression and (possibly duration ) are calculated "on the fly" as audio is being played and whereas applications which process MP3 files can analyse the whole file before playing.

    If you look at LMS Web GUI when plyaing the podcast - the initialduraiton that appears is the one in the feed and shortly after podcast starts playing (i.e. after LMS has been told the number of bytes in the podcast) - LMS updates the duration to the correct longer one. I wonder whether LMS has managed to keep the original feed duration somewhere and didn't update it whereas once you "jump" in the podcasts - LMS knows the real duration.

    Needs some more testing but with much shorter podcast (possibly by faking a feed) .

  4. #14
    Senior Member dolodobendan's Avatar
    Join Date
    Dec 2017
    Location
    Braunschweig, Germany
    Posts
    195
    Quote Originally Posted by bpa View Post
    All duration at teh start of playing an MP3 are estimates based on size and data rate of the file. I'm not sure but I think the data rate is not accurate (i.e. 64kbps will not be 64kbps for 100% of the file but should be the close to that figure for the whole file) it is really a max figure.

    To know exactly the duration of a file without playing it - convert to WAV as part of the conversion the real duration is saved in the header (e.g. lame --mp3input --decode --verbose input.mp3 output.wav ) - there is no compression so duration is accurate.

    LMS treats MP3 podcasts as streams so some values such as compression and (possibly duration ) are calculated "on the fly" as audio is being played and whereas applications which process MP3 files can analyse the whole file before playing.

    If you look at LMS Web GUI when plyaing the podcast - the initialduraiton that appears is the one in the feed and shortly after podcast starts playing (i.e. after LMS has been told the number of bytes in the podcast) - LMS updates the duration to the correct longer one. I wonder whether LMS has managed to keep the original feed duration somewhere and didn't update it whereas once you "jump" in the podcasts - LMS knows the real duration.

    Needs some more testing but with much shorter podcast (possibly by faking a feed) .
    CNN seem to have updated this specific mp3 in some form (it's longer now in LMS and VLC). But to be sure I'd need to have the old feed. I did not anticipate this move and deleted it yesterday.

    Your "jump & update" hypothesis sounds interesting. Maybe LMS just recalculates the duration, thus skipping at the beginning doesn't help playing the mp3 to the end while skipping at the end will. (I assume that the more there is yet to play, the bigger the difference between "real" and "estimated" duration will be.)
    QLMS 7.9.2@1.09a (digimaster) / QNAP 469L QTS 4.3.4

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •