New Project by Import takes long (WAV conversion probably)


Hello Rachana,

we have existing DTBs on DAISY 2.02 format that sometimes we need to rework. We have the mp3, smil, ncc.html.

In order to be able to rework this DTB, I create a new project in OBI by importation, rework it in OBI and export, usual way, nop.

I have a 'philosophical' question ;-): we have noticed that during this OBI import, the time to Import the DTB in OBI is 4 times (yes, 4 times)
as an average to the time needed using Plextalk to do the same (Import the DTB in Plextalk with only the mp3, smil and nc.html)).
For a small book (160 pages) it takes 1 min to Import using Plextalk, using OBI it takes 4 minutes.

Tell me if I am right (or wrong...;-) ), I think this very long time to Import in OBI is due to the audio conversion from MP3 (we only use MP3, at 48kbps or 64kbps) to WAV (I can see the WAV in the Data directory).
1) I am wondering WHY it is needed to convert an existing MP3 in WAV if at the end I will request to Export in DAISY format 2.02 always in MP3 ?
2) Is there a way to 'just' Import the MP3 as is, keep them as MP3, possibly update them in MP3, if I have to do some rework and Export in MP3
as usual ?

May be a new Option in Tools to ask the user if he wishes to only work in MP3 and avoid that heavy WAV conversion ? I know WAV
is of better audio quality than MP3 (even compressed at the 192kbps rate) but here we speak of human voice reading a book, so hi fi quality
is not the point.

Thanks for your help
Eric Houdy

During import, the audio files are converted to WAV to enable audio manipulation. The user can choose to delete chunks of audio, insert or record new audio, split and merge phrases etc. Finally, at the time of export, the audio files can be compressed to MP3. Note that you can export and create a DAISY book keeping the audio files in WAV format.

Currently, it is not possible to keep the files in MP3 format during import.

Hello, thanks for your reply

May be you could add this option to import MP3 as MP3 (no WAV conversion) in your 'wish list' as a wish coming from us, the GIAA ? ;-)

Let me explain you why: we were using only Plextalk to record and produce DTB and are now moving to OBI (we gave our first OBI education sessions for some of our 100
french readers, the ones who record the books in June and July this year). Usually they record the book and DO NOT export to the DAISY format. The Export to the DAISY format is done in our
association because in case there is a problem with the recording, we update the recording or pagination or whatever then at the end we export to the DAISY format.
Using Plextalk with only MP3 for the voice recording, the size of all files (mp3, smil...) is about 150 to 200Mb for 90% of our DTB. Even exported with Plextalk the size of the
DTB is the same (150 to 200Mb). That allows our readers, recording at home, to send us their recording engraving a CD and to post it by 'paper' mail. .
Of course some of them use also USB key to deliver their book if they move to our office. Few of them use 'Dropbox' or 'we transfer' upload.
Now we move to OBI.
If we decide to keep telling our readers to send us their recording in OBI and not to export in DAISY, we need to explain them NOT to engrave a CD because very often with the
WAV files in the DATA directory, the size of all OBI files is from far larger then 1Gb (so not possible to engrave). They would need to use USB key (but are reluctant to send it via mail).
and with such huge amount of data, Dropbox,wetransfer is simply not possible. Our readers are very often 'old' persons (like me ;-) ) meaning over 60 years old and are not
'expert' in computing science....we need to explain them 'easy' ways...
If we decide to ask our readers to Export their OBI project in DAISY format and to send/bring us on a CD or an USB key, then we still need to check their recording. To do so, we need
to Import the DAISY MP3 in OBI (take few minutes due to the WAV conversion), check and possibly update few things, then export again in DAISY format and in MP3 which take quite long
We really need OBI to be able to handle MP3 audio file from Import to Export (no WAV) as an Option of course. If some other OBI users need WAV, nop. But it is quite strange for me
to have an MP3 audio file of 1Mb to import it in OBI, so conversion in WAV files of 11 or 12 Mb (usually the ratio WAV/MP3 is about 11 to 12), then export it again in DAISY format
so from 11 to 12Mb to 1Mb again (with probably loss of the MP3 'quality' of the origin).

Possible ?

Thanks for your support

Hi Eric

Both Obi and Tobi use the common backend, which supports audio editing in wav format. This is to enable audio processing in the future. Wav format can be handled in a better way for editing and processing. MP3 files are mainly used for distribution and not production. If your volunteers want to use MP3 file for transfer of projects, they can export into MP3 and proceed. I think that Fernando in France had worked with such distributed production systems with Obi. Changing the default audio editing format to MP3 is a major piece of work to take up. It will involve refactoring in the common backend.

With regards