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when MP3 is MP2?!

Discussion in 'HD/HDR-FOX T2 Customised Firmware' started by ukayjohn, Aug 22, 2012.

  1. ukayjohn

    ukayjohn Member

    Extracted audio from radio recording, resultant file has .mp3 extension, all lies as we know that it is actually in .MP2 format. I can download to laptop and convert easily enough, but is there a way to do this on-box as it were?.


  2. Ezra Pound

    Ezra Pound Well-Known Member

    MP3 (which is really MPEG 1 or MPEG2 layer 3) is an audio only file, MPEG2 is a video + Audio file. The Web-If extract audio, extacts an audio only file, so I'm not sure why you are calling it an MPEG2 file, I guess it is not the kind of MP3 you was expecting, there are many different sample / bit rates maybe that is what you are getting at
  3. rpb424

    rpb424 Member

    He isn't calling it an MPEG2 (AV) file though, but rather an audio file encoded with the mp2 codec (as is standard in DVB transmissions, not an mp3 codec) then re-wrapped by the webif as mp3, as opposed to being a genuine transcode to mp3. Most players (Apple devices excepted it seems) should play them, but they aren't 'genuine' mp3 without passing them through ffmpeg or similar, and the Humax may not have the necessary grunt to do this.
  4. Ezra Pound

    Ezra Pound Well-Known Member

    Yes there is a difference between MPEG2 layer 3 (Part 3) audio and MPEG2 AAC (part7) audio, although they are both still called MP3 and can usually be played by the same MP3 player
    The Humax uses ffmpeg in order to run the 'extract audio' package
  5. Black Hole

    Black Hole Theloniuos Abbot

    ...but it does no transcoding, it has only been asked to extract streams.
  6. rpb424

    rpb424 Member

    Thanks BH, a detail I should have added.
  7. ukayjohn

    ukayjohn Member

    We got there in the end! is there then a package that will transcode the audio once it has been extracted with ffmpeg?! as it stands, the extracted 'mp3' file will not play or be recognised by the editor/converter of choice on my PC, I can convert using other methods, but this seems like an unecassary extra step in the process.
  8. Ezra Pound

    Ezra Pound Well-Known Member

    I have managed to extract the audio from a radio broadcast TS file using the ffmpeg on the Humax and transcode it to an MP3 file in layer 3 (part 3) rather than AAC (part7) audio, however each 1Meg. of MP3 is taking 3.5 Mins to transcode so the 30 Min. radio program is likely to take 1.5 to 2 Hours to complete, also the CPU resource required is very high, I'm surprised that TV picture hasn't broken up - Yet ! !. So the bottom line is that it is not practicle to convert the file on the Humax while it is being a TV tuner as well - however may-be at night !


    I have just realised that this has all been discussed before HERE