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More => Old Versions => Media Center 17 => Topic started by: terrym@tassie on September 26, 2012, 07:57:46 pm

Title: Low bitrate M4a files showing as 50% of correct duration-garbled playback
Post by: terrym@tassie on September 26, 2012, 07:57:46 pm

Hi I have a problem with some low bitrate m4a files that show as 50% of their correct duration-eg 26minute showing as 13 minute duration- they also don't playback correctly.
I'm using Media Center 17.0.186 on Windows 7.
The files play and display correct duration OK in VLC, Media Player etc.
Example Mediainfo for a file is:
Audio
ID                                       : 1
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : HE-AACv2 / HE-AAC / LC
Codec ID                                 : 40
Duration                                 : 26mn 0s
Bit rate mode                            : Constant
Bit rate                                 : 48.0 Kbps
Channel(s)                               : 2 channels / 1 channel / 1 channel
Channel positions                        : Front: L R / Front: C / Front: C
Sampling rate                            : 44.1 KHz / 44.1 KHz / 22.05 KHz
Compression mode                         : Lossy
Stream size                              : 8.93 MiB (97%)

I don't get the problem with higher bitrate M4a files (128kbps).

Any ideas?

Thanks

Title: Re: Low bitrate M4a files showing as 50% of correct duration-garbled playback
Post by: Lasse_Lus on September 29, 2012, 06:08:12 am

seen this to, also if you change to m4b the duration updates correct but then the bitrate is wrong

Title: Re: Low bitrate M4a files showing as 50% of correct duration-garbled playback
Post by: Matt on September 29, 2012, 08:52:12 am

Welcome.

Would you be willing to send a sample file to matt at jriver dot com?

Thanks.

Title: Re: Low bitrate M4a files showing as 50% of correct duration-garbled playback
Post by: Lasse_Lus on September 29, 2012, 11:18:10 am

matt here you have one http://www.divshare.com/direct/19683272-271.m4a (http://www.divshare.com/direct/19683272-271.m4a)

Title: Re: Low bitrate M4a files showing as 50% of correct duration-garbled playback
Post by: terrym@tassie on September 30, 2012, 05:29:53 am

Thanks for the replies, I'm sending one of the files Matt.
Further to my previous post I have discovered that if I set playback method for for M4a, aac file types from automatic to JRiver audio engine (using DirectShow filter) and reimport the file, it plays back correctly and displays the correct duration.
However if I try and convert the file to Mp3 ( for my Walkman) the file is huge (38Mbytes from a 7 Mbytes source) and the playback is stuttered and garbled.

Title: Re: Low bitrate M4a files showing as 50% of correct duration-garbled playback
Post by: Matt on October 01, 2012, 11:27:32 am

Thanks for the sample file.

Next build of v18:
Fixed: Some low sample rate AAC files that didn't explicitly specify SBR would not play properly.

Maybe you could test it once it's available, and we could decide if it should be rolled back to v17 after that.

Thanks again.

Title: Re: Low bitrate M4a files showing as 50% of correct duration-garbled playback
Post by: terrym@tassie on October 15, 2012, 11:29:13 pm

Hi, I've just upgraded to V18.0.59 and I can confirm that this issue has been fixed. Files now show as correct duration, play back correctly and can be converted to MP3.
As a new user of JRiver MC I have to say I am pleasantly surprised by how quickly the issue was sorted- not my experience with a lot of other software vendors. Good software-good support. I like it! :)