Re: [tsc-devel] Fw: mp3 -> ogg command...

Sydney Dykstra | Mon, 02 Feb 2015 21:38:38 UTC

I wanted to give this a shot, but Debian Jessie does not come with 
ffmpeg anymore. Whats wrong with running it through a audio editing 
program like Audacity? I attached the version of the new Vanilla Dome 
music I converted in Audacity.

https://cloud.openmailbox.org/public.php?service=files&t=a8c6e3231b5e67b8a8582b0c772494dc&download

-Sydney

On 02/01/2015 10:09 PM, Chris Jacobsen wrote:
> For everyone's reference (I was discussing this with Sydney)...
>
>
> On Friday, January 16, 2015 7:14 AM, Quintus <…s@q…> 
> wrote:
>
>
> Hi Chris,
>
> Chris Jacobsen <…9@y… <mailto:…9@y…>> writes:
>
> > If you get a chance later to send me the command you use to convert
> > mp3's to ogg's, I wanted to use it to convert Silensir's song. This
> > would ensure consistent use of compression settings, etc. I could
> > then document it in the wiki so that everyone has this information.
>
> It’s a two-step process. First, you have to determine the bitrate of the
> input file:
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> $ ffmpeg -i <file>.mp3
> [...]
> [mp3 @ 0x7ffdf06767e0] Estimating duration from bitrate, this may be 
> inaccurate
> Input #0, mp3, from 'test.mp3':
>   Duration: 00:01:58.31, start: 0.000000, bitrate: 192 kb/s
>     Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
> At least one output file must be specified
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> That song has a bitrate of 192 kilobyte per second. Now convert it to
> OGG Vorbis with at least that or a higher bitrate (though of course the
> song will not magically gain better quality just if you specify a higher
> bitrate. That would only be possible if you had a lossless FLAC file):
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> $ ffmpeg -i <file>.mp3 -b:a 192k output.ogg
> [...]
> Input #0, mp3, from 'test.mp3':
>   Duration: 00:01:58.31, start: 0.000000, bitrate: 192 kb/s
>     Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
> Output #0, ogg, to 'output.ogg':
>   Metadata:
>     encoder        : Lavf56.15.102
>     Stream #0:0: Audio: vorbis (libvorbis), 44100 Hz, stereo, fltp, 
> 192 kb/s
>     Metadata:
>       encoder        : Lavc56.13.100 libvorbis
> Stream mapping:
>   Stream #0:0 -> #0:0 (mp3 (native) -> vorbis (libvorbis))
> [...]
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> It might be useful to understand how multimedia file formats work. There’s
> generally a “Container” format, in which one or multiple streams of
> “encoded” multimedia data reside. For example, if you have an .ogv video
> file, you have:
>
> 1. Container format: OGG
>   1. Audio codec: Vorbis
>   2. Video codec: Theora
>
> From a more general point of view, there’s no difference between audio
> and video files therefore; from the outside, it looks the same. An OGG
> container may contain only an audio codec, then it’s an audio file. If
> it also contains a video codec, it’s a audio+video file. Only a video
> codec would also be possible.
>
> Not all container formats support all codecs. OGG and Matroska (MKV) are
> formats that support a number of codecs inside them, especially MKV is
> very liberal. The combination of Matroska as the container, Vorbis as
> the audio codec, and VP8 as the Video codec is known as WEBM.
>
> 1. Container format: MKV
>   1. Audio codec: Vorbis
>   2. Video codec: VP8
>
> MP3 also is a container format, but the only codec it supports inside it
> is AAC, which is covered by several unfree software patents. Thus, if
> you say you "convert an MP3 to OGG", what you really do is this:
>
> 1. Container format: MP3 -> OGG
>   1. Audio codec: AAC -> Vorbis
>
> You convert both the container format and the included codec.
>
> A newer alternative to the Vorbis audio codec that recently occured is
> the Opus codec. It is usually packaged inside an OGG container.
>
> 1. Container format: OGG
>   1. Audio codec: Opus
>
> Matroska and OGG are patent-free container formats, Vorbis and Opus are
> patent-free audio codecs. VP8 is to my knowledge the only patent-free
> video codec. Hence, WEBM is the only really free audio+video file
> format. It might be that we see a WEBM2 or whatever format that replaces
> Vorbis with Opus for the audio. I’m personally doing this with my video
> files already and it plays just fine in VLC.
>
> > -Chris
>
> Vale,
>
> Quintus
>
>
> -- 
> Blog: http://www.quintilianus.eu <http://www.quintilianus.eu/>
>
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