Hi, planning to convert some audiobooks for Android. Source files are 128k CBR mp3s, split in chapters. I am looking to save space as well as merge the files into single file with metadata/chapter info.
What audio format and container do you recommend? And, how to effectively create /edit audiobooks in Windows?
Thanks in advance :)
if you can, convert to Opus. Android natively supports Opus starting with 6.0. Technically 5.0 but only inside a Matroska container(stupid i know). If you can't do Opus, vorbis is the second best choice. Or AAC if you need higher compatibility with...something.
My recommendations have to do with coding efficiency. That and I have a really hard to ABXing Opus.
32 kbps AAC-HE.
Or Opus if you have a device that supports it.
I have some experience in this area. You already have them as 128 kbps MP3 files. One of the things you can do to save space is to convert them to mono. Almost all MP3s are 2 channel stereo. Audiobooks, obviously have the same exact audio in both channels, since it is merely somebody reading. You may be able to convert them to mono and cut the file size in half without the need to transcode.
I have posted before in this forum, that I have issues with spoken word only recordings (podcasts, audiobooks) and compression, especially in a car where there is background noise. Lower bitrates, when sent over Bluetooth, I have trouble understanding while driving in a car. I'm sure I have some kind of hearing loss at certain frequencies from all those loud rock concerts in the 80s and 90s. Or some vibration in my car is matches some frequency in spoken word that messes with my hearing.
You might want to experiment with a few of these files transcoded to various bitrates and format and take them in the car with you and see what is most legible to you.
If you're going to be on public transportation, then just get good closed headphones and ignore everything I am saying.
if you can, convert to Opus. Android natively supports Opus starting with 6.0. Technically 5.0 but only inside a Matroska container(stupid i know). If you can't do Opus, vorbis is the second best choice. Or AAC if you need higher compatibility with...something.
My devices run Android 4.4.2 and 5.0. I have Neutron MP installed on both, but it's a battery drainer. :(
Well, how can I put different chapters and titles inside a .mka file? Not going to do it now, just for future purposes.
32 kbps AAC-HE.
Or Opus if you have a device that supports it.
Which HE-AAC encoder would you recommend, Nero or FDK?
Which HE-AAC encoder would you recommend, Nero or FDK?
I would recommend QAAC and Apple encoder. Makeportable can extract required files from installer package so you can use them without iTunes installation.
... Audiobooks, obviously have the same exact audio in both channels, since it is merely somebody reading...
Many audiobooks these days definitely don't fit this description. Rather than "merely somebody reading", many are actually performances, some by a cast of performers. And sound effects and music may also be included.
if you can, convert to Opus. Android natively supports Opus starting with 6.0. Technically 5.0 but only inside a Matroska container(stupid i know). If you can't do Opus, vorbis is the second best choice. Or AAC if you need higher compatibility with...something.
My devices run Android 4.4.2 and 5.0. I have Neutron MP installed on both, but it's a battery drainer. :(
Well, how can I put different chapters and titles inside a .mka file? Not going to do it now, just for future purposes.
32 kbps AAC-HE.
Or Opus if you have a device that supports it.
Which HE-AAC encoder would you recommend, Nero or FDK?
fdk
Adding chapters will be problematic. One possibility would be to mux the audio file into MKV (or MP4) container but almost certainly you would need to manually create a chapter file. As its an MKV file, possibly you audio player of choice wont see this as an audio file but rather video (so something like MX Player for example).
The second choice would be to create a cuesheet for the MP3 file. Some audio players support cuesheet which could then be used to jump to chapters. Cuesheet creation will get a little more complicated if you want to transcode into a single file.
I would suggest you look at foobar. There is a cuesheet creator plug-in available and it also has the ability to output to single file from the convertor.
I would also suggest using the convert to mono DSP if you're OK with mono playback and to also add the DRC (dynamic range compression) DSP in as well. For audio books on Android, I typically use ogg-vorbis with lowest bit-rate VBR. It'll save the hassle of setup for AAC with what I expect will be minimal benefit. I do the same thing but output to MP3 for daughters Kindle. A full audio CD will typically result in an MP3 file about 40MB in size and sound absolutely fine (to me). Of course there's no chapters in this case.
fdk
Advice taken :) Nothing against QAAC, I use it for music. But after a quick check I preferred fdk to Nero and QAAC. Won't be able to tell them apart in blind test though.
Adding chapters will be problematic. One possibility would be to mux the audio file into MKV (or MP4) container but almost certainly you would need to manually create a chapter file. As its an MKV file, possibly you audio player of choice wont see this as an audio file but rather video (so something like MX Player for example).
The second choice would be to create a cuesheet for the MP3 file. Some audio players support cuesheet which could then be used to jump to chapters. Cuesheet creation will get a little more complicated if you want to transcode into a single file.
I would suggest you look at foobar. There is a cuesheet creator plug-in available and it also has the ability to output to single file from the convertor.
I would also suggest using the convert to mono DSP if you're OK with mono playback and to also add the DRC (dynamic range compression) DSP in as well. For audio books on Android, I typically use ogg-vorbis with lowest bit-rate VBR. It'll save the hassle of setup for AAC with what I expect will be minimal benefit. I do the same thing but output to MP3 for daughters Kindle. A full audio CD will typically result in an MP3 file about 40MB in size and sound absolutely fine (to me). Of course there's no chapters in this case.
Indeed, chapters and cue sheets proved to be more trouble than worth. No audio player played a chaptered MP4 file adequately. And, Neutron MP supports cue sheets fine, but it's a battery killer. In the end I just batch transcoded all the mp3s to 32kbps HE-AAC without making a single file and tagged them with artist, album and track number. Now the files show up in all media players as part of the same album, and no problem going back and forth. Not what I would have liked, but this works without problems :)
Seems you have a solution you're OK with but if you're not too far into the transcode process there is another way to achieve single image and cuesheet (so ignoring MKV/MP4 for this). First you would need to transcode the source tracks to FLAC. Then you can use CueTools Image + Cue mode to create a cuesheet. This will also result in a single FLAC file. You don't need this output file; the point is to use CueTools to create the cuesheet which otherwise you'd have to create manually. This cuesheet then only needs minor change to point to your final file (filename and type). Foobar is then use to transcode the individual MP3 files to a single file with the cuesheet used to identify the tracks within (or you could use your intermediary FLAC from before).
if you can, convert to Opus. Android natively supports Opus starting with 6.0. Technically 5.0 but only inside a Matroska container(stupid i know). If you can't do Opus, vorbis is the second best choice. Or AAC if you need higher compatibility with...something.
My recommendations have to do with coding efficiency. That and I have a really hard to ABXing Opus.
wait android support opus without mkv container on 6.0? I have 6.0 and I still can't play opus.
Seems you have a solution you're OK with but if you're not too far into the transcode process there is another way to achieve single image and cuesheet (so ignoring MKV/MP4 for this). First you would need to transcode the source tracks to FLAC. Then you can use CueTools Image + Cue mode to create a cuesheet. This will also result in a single FLAC file. You don't need this output file; the point is to use CueTools to create the cuesheet which otherwise you'd have to create manually. This cuesheet then only needs minor change to point to your final file (filename and type). Foobar is then use to transcode the individual MP3 files to a single file with the cuesheet used to identify the tracks within (or you could use your intermediary FLAC from before).
Great idea, thanks :)
The only drawback now is that cue support is so limited in Android. Well, one can't have everything...
if you can, convert to Opus. Android natively supports Opus starting with 6.0. Technically 5.0 but only inside a Matroska container(stupid i know). If you can't do Opus, vorbis is the second best choice. Or AAC if you need higher compatibility with...something.
My recommendations have to do with coding efficiency. That and I have a really hard to ABXing Opus.
wait android support opus without mkv container on 6.0? I have 6.0 and I still can't play opus.
read somewhere that it does. i guess not. at least the latest poweramp beta does...
Try OBI from Daisy consortium. Supports chapters and full navigation even for Visually Handicapped.
Downmix to mono > Resample to 32kHz > fhgaacenc --vbr 3