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Could we add gapless to Apple's AAC encoder?, task for iTunesencode or other?
guruboolez
post Jun 21 2005, 08:11
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I have a question about a possible new iTunesEncode feature (or any other program driving Apple's AAC encoder). Wouldn't it be possible to add a gapless feature? It might sound silly, but after all, nyaochi did it with the latest Fraunhofer MP3 encoder (here and here). I'm not a coding expert -I'm not a coder at all- but I think that doing it wouldn't be an impossible task.

Adding somewhere in the tags the precise offset (constant for Apple's encoder) and calculating the amount of padded sample maybe suffice? I don't really know. faac and Nero AAC are gapless, and apparently Apple is not hurry to implement this feature. It's a pity, because Apple's encoder is pretty good. Gapless playback is not possible on any iPod, but on a computer (playing with foobar2000 as exemple) users would benefits from it.

Could we reproduce Nyaochi's ACMenc patch to work with iTunes? Or make something similar? What do you think?
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Tropican
post Jun 22 2005, 02:19
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QUOTE (nyaochi @ Jun 21 2005, 07:40 PM)
We need: 1) encoder delay of iTunes AAC encoder; 2) number of padded silent samples at the end of stream by iTunes (of course it's not constant)
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How did you find the delay of the FhG encoders nyaochi? How exactly is an encoder delay determined in any format, or is it format specific?

Removing silent samples has been done so many times in audio editors that it shouldn't be a problem. Or will removing silent samples that aren't padded ones by iTunes cause even bigger problems?

QUOTE (nyaochi @ Jun 21 2005, 07:40 PM)
I'm not sure how AAC gapless is achieved
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There's the FAAC source.

Please no developers take this as an insult. Note that I'm minimizing the amount of work this would take as I'm

1) Not a programmer
2) Someone who really would like to see someone at least attempt to do this, and am worried that the amount of time this would need may scare some talented people away, so is unestimating the time on such a project greatly
3)Am afraid that when iTunes receives VBR support from Quicktime 7, even if the quality ends up being better than Nero, most users here will have to stick with Nero for gapless.


There's always the chance Apple will add support themselves smile.gif
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nyaochi
post Jun 22 2005, 03:11
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QUOTE (Tropican @ Jun 22 2005, 10:19 AM)
How did you find the delay of the FhG encoders nyaochi?  How exactly is an encoder delay determined in any format, or is it format specific?

Lookint at this page to guess the delay, I measured and confirmed the value by using a wave editor.

QUOTE (Tropican @ Jun 22 2005, 10:19 AM)
Removing silent samples has been done so many times in audio editors that it shouldn't be a problem.  Or will removing silent samples that aren't padded ones by iTunes cause even bigger problems?

You missed the point. AAC stream seems to have 1024 frame size, which means that you will/must get 1024*n samples after decoding an AAC stream. That's one reason why iTunes must pad silent samples to fill the last frame. And there's another reason from encoder delay, but I don't mention here. Anyway, the necessary task is not removing the silence, but telling a decoder the number of samples to be removed for playback. It cannot be achieved by an audio editor.

QUOTE (Tropican @ Jun 22 2005, 10:19 AM)
There's the FAAC source.

Please no developers take this as an insult.  Note that I'm minimizing the amount of work this would take as I'm

1) Not a programmer
2) Someone who really would like to see someone at least attempt to do this, and am worried that the amount of time this would need may scare some talented people away, so is unestimating the time on such a project greatly
3)Am afraid that when iTunes receives VBR support from Quicktime 7, even if the quality ends up being better than Nero, most users here will have to stick with Nero for gapless.


There's always the chance Apple will add support themselves  smile.gif
*

Of course I saw the FAAC source. I understand your feeling to minimize/simplify the problem. But the problem cannot be simplified as you expected. The simplest solution would be something like what I wrote in the previous post, which talented people won't scare.
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Posts in this topic
- guruboolez   Could we add gapless to Apple's AAC encoder?   Jun 21 2005, 08:11
- - Otto42   Short answer: no. Long answer: yes, but I'm n...   Jun 21 2005, 18:25
|- - Mike Giacomelli   QUOTE (Otto42 @ Jun 21 2005, 09:25 AM)Short a...   Jun 22 2005, 05:35
|- - Gabriel   QUOTE How would you get the encoder delay out of i...   Jun 22 2005, 08:56
- - Tropican   This may be a dumb question, but if the encoding d...   Jun 21 2005, 23:55
- - nyaochi   I don't know much about AAC and MP4 container ...   Jun 22 2005, 01:40
- - Tropican   QUOTE (nyaochi @ Jun 21 2005, 07:40 PM)We nee...   Jun 22 2005, 02:19
|- - nyaochi   QUOTE (Tropican @ Jun 22 2005, 10:19 AM)How d...   Jun 22 2005, 03:11
- - Tropican   Sorry, my last post was poorly written. QUOTE (ny...   Jun 22 2005, 04:10
- - Tropican   QUOTE (Gabriel @ Jun 22 2005, 02:56 AM)you ha...   Jun 22 2005, 22:31
- - M   Pardon my ignorance on the technicalities involved...   Jun 23 2005, 02:37
|- - soundcheck   QUOTE (M @ Jun 22 2005, 09:37 PM)Pardon my ig...   Jun 23 2005, 06:31
|- - bond   QUOTE (soundcheck @ Jun 23 2005, 07:31 AM)QUO...   Jun 23 2005, 20:20
|- - soundcheck   QUOTE (bond @ Jun 23 2005, 03:20 PM)QUOTE (so...   Jun 23 2005, 23:06
|- - bond   QUOTE (soundcheck @ Jun 24 2005, 12:06 AM)The...   Jun 24 2005, 09:22
|- - soundcheck   QUOTE (bond @ Jun 24 2005, 04:22 AM)hm could ...   Jun 24 2005, 21:00
- - Mono   Actually that's Apple's official stance: Q...   Jun 23 2005, 04:13
- - westgroveg   I think guruboolez needs CASE.   Jun 23 2005, 05:55
- - bond   ok so its seems to be indeed a non-mp4 file, thx...   Jun 25 2005, 10:09
|- - soundcheck   QUOTE (bond @ Jun 25 2005, 05:09 AM)ok so its...   Jun 25 2005, 18:29
|- - M   QUOTE (soundcheck @ Jun 25 2005, 12:29 PM)I t...   Jun 25 2005, 19:13
- - bond   can you run mp4box's -info on the itunes audib...   Jun 25 2005, 19:05
- - nyaochi   Since no one seems to take this task, I read the s...   Jun 27 2005, 03:04
|- - rjamorim   QUOTE (nyaochi @ Jun 26 2005, 11:04 PM)Does a...   Jun 27 2005, 03:57
|- - Juho Vähä-Herttua   I just implemented true gapless playback of AAC fi...   May 2 2006, 13:56
- - bond   somehow i get the feeling that this "hacking...   Jun 27 2005, 09:59
- - nyaochi   Thanks for the info, rjamorim and bond To summa...   Jun 27 2005, 12:03
- - Tropican   QUOTE (nyaochi @ Jun 27 2005, 06:03 AM)1) but...   Jun 29 2005, 02:58
- - loophole   http://www.apple.com/quicktime/tutorials/chaptertr...   Jun 29 2005, 05:04
|- - Fofer   Great info here, looks like this is a great way fo...   Jul 10 2005, 17:04
- - cvkslashdot   Check my tutorial w/ images if you have a mac: ht...   Jul 20 2005, 01:15
- - Otto42   This isn't really "gapless" as I see...   Jul 20 2005, 16:35
- - nyaochi   I bet Apple will implement the gapless feature in ...   Jul 20 2005, 16:49
- - e-San   I know topic seems to be dead but i am quite shure...   Mar 28 2011, 09:10


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