Strona domowa GDR!a Tor Hidden Service

V 3.8



Tremor i ivorbisfile_example

(16. 10. 2007)

Kompilowałem dziś bibliotekę Tremor (stałoprzecinkowa implementacja libvorbis do odtwarzania OGG) pod Visual C++ 2005. Sama biblioteka zbudowała się bez żadnego problemu po użyciu załączonego pliku projektu, niestety inaczej było z przykładowym dekoderem umieszczonym w pliku ivorbisfile_example.c. Brakowało mu eksportów umieszczonych zazwyczaj w libvorbisfile - _ov_clear i inne zaczynające się od _ov. Po przydługiej kombinacji z budowaniem libvorbisfile z libvorbis i łaczeniem jej z Tremorem zauważyłem ciekawy plik znajdujący się w samym Tremorze. Nazywał się vorbisfile.c i - jak się okazało - nie był dołączony do domyślnego projektu, przez co biblioteka kompilowała się bez dostarczanych przez niego eksportów. Dodanie go do projektu załatwiło wszystkie problemy z kompilacją. Cóż, zawsze to jakaś nauczka na przyszłość.

Obsługa samego ivorbisfile_example.exe sprowadza się do ivorbisfile_example.exe <"Pijak Potrafi - Arise (main tune).ogg" >out.raw i potem - żeby odtworzyć plik - konwersji do formatu wav za pomocą SoXa: sox -r 44100 -s -w -c 1 -t raw out.raw out.wav

A cała ta zabawa potrzebna była do pracy przejściowej na studia - wynikiem ma być wersja kodeka dająca zaimplementować się w sprzęcie. W sprzęcie czyli nie na mikrokontrolerze, tylko w postaci układu scalonego bądź FPGA. Zobaczymy co z tego wyjdzie.

(komentarzy: 1, ostatni: 21. 08. 2012 - 05:34:35 - lLlMgtwoWKgMsSvv) Skomentuj
Wyswietlen: 2781, komentarzy: 1 Feed z komentarzami


Imię: lLlMgtwoWKgMsSvv (21. 08. 2012 - 05:34:34)

Treść:
Yeah I remember doing the ceinorsvon of a few hundred speaker cassette tapes into the only converter I could get at the time, which was that DREADFUL Real Media PRODUCER, that wasn't bad in the quality of encoding, it was just almost NOTHING in the way of portable audio players, used the format.But after doing all the ceinorsvons to digital, I had disposed of all the tapes . Bummer.AND it was at this point that I became aware of the EVILNESS of the REAL MEDIA formats and their attitude toward consumers, NO I don't want to install, this, that, these things, those things, and a number of other things .And they rigged their software to go right ahead and install everything I specifically cited, that I did not want installed, and they effectively overran my PC with their software.BAD moves.Real Media were focused on proprietary lock in and using underhanded tactics, at my expense, to achieve it. Kind of like getting a simple savings account and then finding it linked to a super high interest rate credit card and getting ripped off when withdrawing YOUR OWN money .. that's right not their money, your own money, at their credit card interest rate.That kind of an underhanded ethical scam A few years down the track along came some FREE (?) software that enabled me to DECONVERT from the RM, RAM, RA Real Media format/s, and into MP3 format.I had to make an awful lot of data fit onto small drives etc., so I understand everything to do with high compression ratios but there comes a point where the compression is so high, and the audio quality is so low, that some basic principles have to be implemented.Stupidity, very high compression and really poor quality audio is to no ones advantage. It's like scumming on ink so badly, by thinning it out so much and then spraying down so little that no one can read the ghost font .That is where the true advantages of compression is lost.File compression (in audio) has it's origins in the days of floppy disk drives, very small hard drives, slow motherboards, low strength processors, very expensive low spec RAM and low capacity internet speeds meets the coming tidal wave of digitisation of audio and video.Now for many people there is NO advantage for minimalist quality audio and video, in fact it's much better to have reasonably good compression and very good sound quality.So while I have done very good combinations of 56kpbs and sampling rate audio and come up with high clarity and just a fractional tinniness I am not sure that it's a brilliant move, but because real sound quality from high compression needs to be done on the basis of sound quality first and file size second.This becomes an issue when one has hundreds of thousands of audio files .. but rather than abandon the high compression levels, I'd be looking at the quality of the encoding rates.If you can achieve near identical sound quality for the entire 50 years of the hour long weekly Roy Rogers Cowboy Radio Show, at about 30% of the file size, as compared to just slack 128Kbps with a low sampling rate, I'd got the 56Kbps with a higher sampling rate.High quality compression isn't just the compression it's the settings of the compression engine that make a huge amount of difference in the quality of the finished product.Before you write off the high compression formats experiment with the settings of the high compression levels, such as the sampling rate.I think I used 56Kbps audio quality compression level at a 44 or a 64 or 96Khz sampling rate. Been a long time since I did it .I got sanely small file sizes and very good quality audio especially good on speaker tapes . and radio quality broadcasting.Then it was dor

Sblam! Antyspam
URL encoded in QR Code Statystyki:

Email
Comments