HydrogenAudio

Lossy Audio Compression => Ogg Vorbis => Ogg Vorbis - Tech => Topic started by: RutinTutinPootin on 2021-01-06 06:57:57

Title: Audio on replay is different
Post by: RutinTutinPootin on 2021-01-06 06:57:57
I had a friend show me an ogg file that when played starts a just a 1 second snip of audio. But when replaying it different audio was played. This also has different effects in the different players i try: Windows just plays the 1 second part, VLC audio is messed up completely with it sounding weirdly distorted. Audacity won't even attempt to read it.
 I'm thinking the headers were edited but wanted the ideas of people who are better at this stuff then i am.
Title: Re: Audio on replay is different
Post by: itisljar on 2021-01-06 10:37:49
It would be nice if we could have that file uploaded somewhere to check out.
Title: Re: Audio on replay is different
Post by: RutinTutinPootin on 2021-01-06 14:08:31
Yea here you go im an idiot for not including it in the OP.
Title: Re: Audio on replay is different
Post by: john33 on 2021-01-06 14:35:46
Almost all the header information is missing. None of the information regarding the bitstream is present so it's hardly surprising that it won't play.
Title: Re: Audio on replay is different
Post by: RutinTutinPootin on 2021-01-06 16:27:38
It does play with varying results depending on the player, the webplayer leaves a part of the ending out, windows built in player plays 1 second with the last bit repeating once, VLC plays the audio with a weird pitch distortion on it. Do you think the bitstream of the file is the sole reason the file is acting the way it does? I'm more curious as to how it works rather then to why it plays differently on other players.
Title: Re: Audio on replay is different
Post by: john33 on 2021-01-06 17:40:52
I'm guessing that because it seems to have at least part of the ogg container header, the players may be assuming that a vorbis stream follows but oggdec does not recognise it as a valid file and neither does foobar2000.
Title: Re: Audio on replay is different
Post by: itisljar on 2021-01-06 18:06:16
Hahaha!
So, it plays this:

anime girlish voice: HEY! LISTEN! and it plays never gonna give you up from rick astley in bad quality. I am going to let it play till the end, to see if it continues... :)
(edit: it ends normally. Played with Bomi player, some fork of mplayer or something...)

Speed is normal, no artifacts except those from 64kbit encoding, but it sounds worse than 64kbit, I think it's distorted for meme purposes.
So, it can be played on Bomi, which isn't maintained, but it plays also in BakaMplayer, newest version as of this date. There you go.
Title: Re: Audio on replay is different
Post by: j7n on 2021-01-07 00:21:35
The file appears to be concatenated from clips of several other sound files. There is a section of silent MP3 frames among others. The Rick Astley song is boosted in level and plays without distortion with about -14 db gain. It is recognized as a subsong in Foobar 0.8.3.
Title: Re: Audio on replay is different
Post by: DVDdoug on 2021-01-07 17:52:03
If you (or your friend) can play it (or play the part you want) Audacity can record whatever is playing on your computer.   Then of course, you can save it as a new file.  
Title: Re: Audio on replay is different
Post by: ajp9 on 2021-01-07 20:17:41
The file data looks like it's been set up for some kind of streaming the way it's not comprised of one Ogg header for one overall Vorbis stream, but five stream header signatures. It plays fine in FireFox (can handle concatenated streams), but won't allow you to seek; restarting the audio requires reloading the file. Attempting to load it in Audacity only loads the first 1 second stream.

Addendum: I'm using FireFox 84.0.2 and Audacity 2.1.2.
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