Specifying the bitrate for transcode from WAV to Speex SPX/O

[dvogel]

Since speexenc doesn't support non-PCM .wav files, I am trying to use VLC to transcode my m-law .wav files using the Speex encoder. The conversion is working, but the resulting file size is much higher than I expected. The original .wav file is 0:05 duration, 65,594 bytes while the resulting .spx.ogg file is 26,985 bytes.

According to VLC's View Stream and Media Info, the .spx.ogg bitrate is 4294967 kb/s -- absurd considering the filesize is so small. This is the command line I used:

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"c:\Program Files\VideoLAN\VLC\vlc.exe" -vvv in.wav :sout= "#transcode{aenc=speex}:standard{access=file,mux=ogg,url=out.spx.ogg}" vlc:quit

If I try to specify the bitrate, as shown below, the resulting file is exactly the same.

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"c:\Program Files\VideoLAN\VLC\vlc.exe" -vvv in.wav :sout= "#transcode{aenc=speex,ab=64}:standard{access=file,mux=ogg,url=out.spx.ogg}" vlc:quit

Could someone give me a working command line or point me to a (more) complete list of options available for the speex encoder?

[Nil Einne]

Well unfortunately from my own tests and taking a quick look at the source code, there seems to be very little control over the speex codec. For example control over the comp, quality, vbr/abr and other options seems to be missing. I thought I managed to get ultra-wideband when testing before but I'm unable to when I try now so I think I'm wrong (also from looking at the source). Even bitrate control doesn't seem to work as you point out. However I noticed some potential problems with your options. Here's what I use and it works with very small files. E.g I'm able to encode nearly 2 hours in 20 mb. Here's what I use

:sout=#transcode{threads=2,samplerate=8000,acodec=spx,aenc=speex,ab=8,channels=1}:duplicate{threads=2,dst=std{access=file,mux=ogg,dst="c:\oggspeex",threads=2}} :no-sout-video

I don't think you need to specify threads=2 so many times but I did it anyway just in case since I was a bit confused by the options Also the ab option doesn't seem to do anything. The key thing you may be missing is samplerate conversion. Speex narrowband is designed for 8000hz and if you don't convert it it just accepts it but if it's something like 16000hz or larger it'll be very large. If your source is already 8000hz then there's nothing you can do. 11025 is supported by narrowband but they say your mileage may vary. You may want to look into samplerate conversion in VLC and see if there are options which may give better quality. Also if you have a stereo source remember to convert to mono unless you really want the stereo.

Edit: Actually there appears to be a major problem with what I'm doing. I just compared it to what I get from the speex command line encoder and the file I'm getting from Ogg is a lot larger. It's slightly larger then quality=10 for CBR but it's actually quality=8. No idea why, I'll try some more later. I don't get it, perhaps there's something wrong with the muxing settings
Edit2: Confirmed since if I use raw the file is about right except it doesn't play

P.S. I think you can potentially specify MAX_FRAME_SIZE and MAX_FRAME_BYTES but I'm not sure. Doesn't seem useful to me so I haven't tried

[Nil Einne]

I've made a feature request viewtopic.php?f=7&t=40558 BTW