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  1. Member
    Join Date
    Sep 2014
    Location
    Russia
    Search Comp PM
    Could someone tell me why the sound is not working on IPodf ( on PC the sound works ok ) for the following file :

    Thank you!


    General
    Complete name : alofp.mp4
    Format : MPEG-4
    Format profile : Base Media
    Codec ID : isom
    File size : 42.5 MiB
    Duration : 22s 990ms
    Overall bit rate mode : Variable
    Overall bit rate : 15.5 Mbps
    Encoded date : UTC 2014-09-24 12:54:41
    Tagged date : UTC 2014-09-24 12:54:41
    Writing application : Lavf51.12.1

    Video
    ID : 1
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : Baseline@L4.0
    Format settings, CABAC : No
    Format settings, ReFrames : 1 frame
    Format settings, GOP : M=1, N=12
    Codec ID : avc1
    Codec ID/Info : Advanced Video Coding
    Duration : 22s 990ms
    Bit rate : 15.3 Mbps
    Width : 1 920 pixels
    Height : 1 080 pixels
    Display aspect ratio : 16:9
    Frame rate mode : Constant
    Frame rate : 29.970 fps
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Progressive
    Bits/(Pixel*Frame) : 0.247
    Stream size : 42.0 MiB (99%)
    Language : English
    Encoded date : UTC 2014-09-24 12:54:41
    Tagged date : UTC 2014-09-24 12:54:41

    Audio
    ID : 2
    Format : AAC
    Format/Info : Advanced Audio Codec
    Format profile : LC
    Codec ID : 40
    Duration : 22s 919ms
    Bit rate mode : Variable
    Bit rate : 144 Kbps
    Channel(s) : 2 channels
    Channel positions : Front: L R
    Sampling rate : 44.1 KHz
    Compression mode : Lossy
    Stream size : 408 KiB (1%)
    Language : English
    Encoded date : UTC 2014-09-24 12:54:41
    Tagged date : UTC 2014-09-24 12:54:41
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  2. DECEASED
    Join Date
    Jun 2009
    Location
    Heaven
    Search Comp PM
    Perhaps because it was muxed by:
    Writing application : Lavf51.12.1
    Try remuxing with MP4Box, which has an -ipod option.
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  3. Member
    Join Date
    Sep 2014
    Location
    Russia
    Search Comp PM
    MP4box said : Muxing failed.
    Still, it outputed a file for which mediainfo says what I put below. I have no way to check if it works on apple devices yet. Do you think it will work on IPad.Iphone/Ipod this time ?

    Thank you!
    Correx.

    General
    Complete name : F:\mov\alofp.mp4
    Format : MPEG-4
    Format profile : Base Media
    Codec ID : isom
    File size : 41.6 MiB
    Duration : 22s 988ms
    Overall bit rate mode : Variable
    Overall bit rate : 15.2 Mbps
    Encoded date : UTC 2014-09-23 18:38:49
    Tagged date : UTC 2014-09-23 18:38:49

    Video
    ID : 1
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : Baseline@L4.0
    Format settings, CABAC : No
    Format settings, ReFrames : 1 frame
    Format settings, GOP : M=1, N=12
    Codec ID : avc1
    Codec ID/Info : Advanced Video Coding
    Duration : 22s 988ms
    Bit rate : 15.0 Mbps
    Maximum bit rate : 29.0 Mbps
    Width : 640 pixels
    Height : 768 pixels
    Display aspect ratio : 0.833
    Frame rate mode : Constant
    Frame rate : 29.970 fps
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Progressive
    Bits/(Pixel*Frame) : 1.020
    Stream size : 41.2 MiB (99%)
    Language : English
    Encoded date : UTC 2014-09-24 12:44:55
    Tagged date : UTC 2014-09-23 18:38:49

    Audio
    ID : 2
    Format : AAC
    Format/Info : Advanced Audio Codec
    Format profile : LC
    Codec ID : 40
    Duration : 22s 917ms
    Bit rate mode : Variable
    Bit rate : 144 Kbps
    Maximum bit rate : 200 Kbps
    Channel(s) : 2 channels
    Channel positions : Front: L R
    Sampling rate : 44.1 KHz
    Compression mode : Lossy
    Stream size : 408 KiB (1%)
    Language : English
    Encoded date : UTC 2014-09-23 18:38:49
    Tagged date : UTC 2014-09-23 18:38:49
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  4. DECEASED
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    Jun 2009
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    Heaven
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    Originally Posted by correx View Post
    I have no way to check if it works on apple devices yet. Do you think it will work on IPad.Iphone/Ipod this time ?
    Sorry, I have zero devices made by Apple.

    Now I think it's possible that the AAC stream itself is somehow non-compliant or broken...
    and in this case, a mere remux will be pointless

    Suggested workaround: use ffmpeg to decode the audio to an uncompressed .WAV file,
    re-encode this latter with fhgaacenc or qaac,
    remux the original video with the re-encoded audio,
    TEST.
    Last edited by El Heggunte; 25th Sep 2014 at 05:53.
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  5. If I remember correctly..... and I may be wrong..... but I kind of remember the maximum AAC audio bitrate is 160kbps and it must be constant bitrate. I don't own an ianything either though so maybe someone else will know.
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  6. DECEASED
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    @hello_hello: the maximum bitrate for AAC is 256kbps per channel.

    BTW, we still don't know whether the MP4 file was created by the OP themselves, or gotten from elsewhere...

    I have already seen borked MP3 streams that could be played correctly, or at all, only through MPlayer...

    and now I also think that similarly-broken AAC streams can be generated by some obscure/half-assed AAC encoder(s)...
    Last edited by El Heggunte; 26th Sep 2014 at 09:50. Reason: clarity
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  7. Member Cornucopia's Avatar
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    Not sure what the max actually is supposed to be (it is probably different for mono vs. stereo/2ch vs. 5.1), but for stereo it is listed in Wikipedia as 529kbps. I know for a fact that, when using LameXP, I can do up to 400kbps (stereo). And it can do CBR AND VBR (and ABR and VBR-constrained).

    Now, how well MacOS or iOS apps & devices accept the range of the spec, I also have no idea. Of course, it took forever before Quicktime even accepted AAC-HE (vs. AAC-LC), so go figure. I know QT7proWin can both encode & decode up to 320kbps, and it is usually the most "crippled" of the QT products, so I'm confident that pretty much every QT-based (and this includes AVFoundation-based as well) app/device should at least be able to do that.

    Scott

    AAH...El Heggunte beat me to it!
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  8. Originally Posted by El Heggunte View Post
    @hello_hello: the maximum bitrate for AAC is 256kbps per channel.
    I was referring to what an ipod will play, not the AAC spec itself. This is from the first ipod specs I found via Google. I don't know which iflavour of ipod the OP owns. I think the ipad is the same.

    iPod touch 16GB (5th generation, Mid 2013)
    Audio
    AAC (8 to 320 Kbps), Protected AAC (from iTunes Store), HE-AAC, MP3 (8 to 320 Kbps), MP3 VBR, Audible (formats 2, 3, 4, Audible Enhanced Audio, AAX, and AAX+), Apple Lossless, AIFF, and WAV
    TV and Video
    H.264 video up to 1080p, 30 frames per second, Main Profile level 4.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats

    As I said, I've never owned an ianything but I remember the 160kbps being a constant bitrate. It seems odd VBR MP3 is specified but for AAC it's not, although AAC needing to be constant bitrate.... maybe I imagined it.
    I assume only stereo (or mono) audio is supported, although the audio is stereo in this case.
    Last edited by hello_hello; 26th Sep 2014 at 13:00.
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  9. Member
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    Russia
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    Hey guys,
    I sent the result file to whom it requested it from me, but unfortunately I got no feedback ( yet, maybe ).
    The only thing I can say is that, the original .mov file , from which I made ( using xilisoft ) the mp4 file described in my first post , played fine on mplayer and vlc, but did not play correctly in media player classic ( not even video ) and I couldn't even add it to Itunes library.
    For the moment I don't need to solve this anymore, but thank a tone to all of you for you efforts!
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