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I did a podcast/audiobook player app ('lectr') with gap removal and had experimental support for what you describe. Roughly, it removed samples if there was no

I did a podcast/audiobook player app ('lectr') with gap removal and had experimental support for what you describe. Roughly, it removed samples if there was no significant difference in the frequency-domain spectra. This was a simple threshold test (the threshold could be adjusted by the user). It works for some material. Some speakers (usually professional book readers) have even pacing and it's more effective. A simple 1.5-1.7x speedup is also useful there. Podcasters tend to be 'bursty' in that they speak rapidly and then pause, and gap removal was more useful there. I stopped working on it as my lifestyle changed such that I wasn't using it. There was almost no commercial interest in the project. I'd love to see a library, especially with MOOCs etc becoming mainstream. Most players provide 1.25/1.5/2.0x options, but between 1.5x and 2.0x is the sweet spot for me, and almost no apps provide that.

jessriedel 10y ago
Thanks for your insightful comment! Is Lectr still available anywhere? Nothing showed up on a Google search. > between 1.5x and 2.0x is the sweet spot for me, and almost no apps provide that. Agreed, this is super frustrating and is some evidence that the market isn't that interested. (Why would they pay for advanced compression if no one bothers with trivial stuff like finer gradation?) Fwiw, on Android I use Audible, PocketCasts, and Audipo for audiobooks, podcasts, and general audio, respectively. They are all serviceable and have 0.1x or finer granularity.
- MaulingMonkey 10y ago
  HTML5 video speed can be controlled with a bookmarklet on Desktop at least: javascript:document.getElementsByTagName("video")[0].playbackRate=4 You probably don't want my 4x speed as chosen here ;)
- ianhowson 10y ago
  Not available any more. It was for iOS. I pulled it from the App Store a few iOS releases ago because it was crashing on startup. I've taken the website down but you can still view it on archive.org: http://web.archive.org/web/20160329053206/http://www.lectrapp.com/ http://web.archive.org/web/20160329053206/http://www.lectrap... I still use Swift for finer gradation. It also worked for video files, which was fantastic (mine never did that). Swift is 32-bit and will stop working soon. I haven't found a replacement yet. (On iOS, at least, the 1.25/1.5/2.0 thing is because that's what the OS provides for very little effort. Finer controls require use of a supported-but-undocumented API or AudioUnits.)

jessriedel 10y ago

Thanks for your insightful comment! Is Lectr still available anywhere? Nothing showed up on a Google search. > between 1.5x and 2.0x is the sweet spot for me, and almost no apps provide that. Agreed, this is super frustrating and is some evidence that the market isn't that interested. (Why would they pay for advanced compression if no one bothers with trivial stuff like finer gradation?) Fwiw, on Android I use Audible, PocketCasts, and Audipo for audiobooks, podcasts, and general audio, respectively. They are all serviceable and have 0.1x or finer granularity.

MaulingMonkey 10y ago
HTML5 video speed can be controlled with a bookmarklet on Desktop at least: javascript:document.getElementsByTagName("video")[0].playbackRate=4 You probably don't want my 4x speed as chosen here ;)
ianhowson 10y ago
Not available any more. It was for iOS. I pulled it from the App Store a few iOS releases ago because it was crashing on startup. I've taken the website down but you can still view it on archive.org: http://web.archive.org/web/20160329053206/http://www.lectrapp.com/ http://web.archive.org/web/20160329053206/http://www.lectrap... I still use Swift for finer gradation. It also worked for video files, which was fantastic (mine never did that). Swift is 32-bit and will stop working soon. I haven't found a replacement yet. (On iOS, at least, the 1.25/1.5/2.0 thing is because that's what the OS provides for very little effort. Finer controls require use of a supported-but-undocumented API or AudioUnits.)