Add ability to configure audio encoding

Still can't do pass-through though...

Fixes: #5

docs/settings.rst

@@ -19,6 +19,7 @@ application).
    var_api_url
    var_atomicparsley
    var_audio_all
+   var_audio_encoding
    var_audio_langs
    var_audio_mix
    var_decomb

docs/var_audio_encoding.rst

@@ -0,0 +1,75 @@
+.. tvrip: extract and transcode DVDs of TV series
+..
+.. Copyright (c) 2024 Dave Jones <dave@waveform.org.uk>
+..
+.. SPDX-License-Identifier: GPL-3.0-or-later
+
+==============
+audio_encoding
+==============
+
+::
+
+    set audio_encoding <encoding>
+
+This setting specifies the encoder used for audio tracks on the ripped titles.
+The valid values are:
+
+``av_aac``
+    The default AAC encoder included with libav. This generally produces good
+    results in most cases at bitrates over 160kbps, but can struggle with
+    particular types of noise (wind noise in certain scenes has been known to
+    cause issues)
+
+``fdk_aac``
+    The Fraunhofer AAC encoder. This generally produces good results at
+    bitrates over 160kbps.
+
+    .. warning::
+
+        Most builds of HandBrake do *not* include this codec as it is still
+        under patent in many jurisdictions.
+
+``fdk_haac``
+    The Fraunhofer HE-AAC encoder. This produces good results in most cases at
+    bitrates over 96kbps. Be aware that many players do not support HE-AAC
+    decoding.
+
+``mp3``
+    The LAME MP3 encoder. This produces good results at bitrates over 192kbps.
+    Be aware that some players will not support MP4 sources containing MP3
+    audio streams (such players tend to support AAC audio within MP4 only).
+
+``vorbis``
+    Xiph's Vorbis encoder. This produces good results at bitrates over
+    160kbps. Be aware that, despite being an open format, support for Vorbis
+    decoding in players is relatively poor.
+
+``opus``
+    Xiph's Opus encoder (the successor to the Vorbis format). This produces
+    good results at bitrates over 96kbps. Be aware that, despite being an open
+    format, support for Opus decoding in players is relatively poor.
+
+``flac16`` or ``flac24``
+    Xiph's FLAC encoder. As a lossless format, this guarantees no degradation
+    in audio, but the compression is nowhere near that achieved by the lossy
+    codecs (typical bitrate is between 800 and 1400kbps). The number on the
+    end determines whether 16-bit or 24-bit samples are used.
+
+    .. note::
+
+        There is almost never a point to using ``flac24`` in ripping DVDs as
+        they use 16-bit audio samples. There *may* be a use for ``flac24``
+        when ripping Blu-ray, but you'd need to query the source to discover if
+        it's actually using more than 16-bit audio samples.
+
+``ac3`` or ``eac3``
+    Dolby's AC-3 and E-AC-3 encodings. AC-3 is the native encoding used on DVD
+    discs, and produces very good quality, but as a rather old encoding it has
+    a rather high bitrate due to poor (by modern standards) compression. It is
+    common to find bitrates of 384kbps or greater on DVDs.
+
+
+.. note::
+
+    Audio pass-through is not currently supported in tvrip.

tests/test_ripcmd.py

@@ -570,6 +570,7 @@ def test_do_config(db, with_program, ripcmd, reader, tmp_path):
 │ decomb           │ auto
 │ audio_mix        │ dpl2
 │ audio_all        │ off
+│ audio_encoding   │ av_aac
 │ audio_langs      │ eng
 │ subtitle_format  │ none
 │ subtitle_all     │ off
@@ -594,7 +595,8 @@ def test_do_set(ripcmd):
 def test_complete_set(ripcmd):
     assert completions(ripcmd, 'set foo') == []
     assert completions(ripcmd, 'set dvd') == ['dvdnav']
-    assert set(completions(ripcmd, 'set audio')) == {'audio_mix', 'audio_all', 'audio_langs'}
+    assert set(completions(ripcmd, 'set audio')) == {
+        'audio_mix', 'audio_all', 'audio_langs', 'audio_encoding'}
     assert completions(ripcmd, 'set foo bar') is None
     assert completions(ripcmd, 'set template foo') is None
 
@@ -837,6 +839,22 @@ def test_complete_set_audio_mix(db, with_config, ripcmd):
     assert set(completions(ripcmd, 'set audio_mix s')) == {'stereo', 'surround'}
 
 
+def test_set_audio_encoding(db, with_config, ripcmd):
+    with db.transaction():
+        assert ripcmd.config.audio_encoding == 'av_aac'
+        ripcmd.do_set('audio_encoding mp3')
+        assert ripcmd.config.audio_encoding == 'mp3'
+        with pytest.raises(CmdError):
+            ripcmd.do_set('audio_encoding foo')
+
+
+def test_complete_set_audio_encoding(db, with_config, ripcmd):
+    assert completions(ripcmd, 'set audio_encoding z') == []
+    assert completions(ripcmd, 'set audio_encoding m') == ['mp3']
+    assert set(completions(ripcmd, 'set audio_encoding fl')) == {
+        'flac', 'flac16', 'flac24'}
+
+
 def test_set_subtitle_format(db, with_config, ripcmd):
     with db.transaction():
         assert ripcmd.config.subtitle_format == 'none'

tvrip/ripcmd.py

@@ -55,6 +55,7 @@ def __init__(self, db, *, stdin=None, stdout=None):
             'api_url':          self.set_api_url,
             'atomicparsley':    self.set_executable,
             'audio_all':        self.set_bool,
+            'audio_encoding':   self.set_audio_encoding,
             'audio_langs':      self.set_langs,
             'audio_mix':        self.set_audio_mix,
             'decomb':           self.set_decomb,
@@ -467,6 +468,7 @@ def do_config(self, arg=''):
         table.add_row('decomb', self.config.decomb)
         table.add_row('audio_mix', self.config.audio_mix)
         table.add_row('audio_all', bool_str[self.config.audio_all])
+        table.add_row('audio_encoding', self.config.audio_encoding)
         table.add_row('audio_langs', ' '.join(self.config.audio_langs))
         table.add_row('subtitle_format', self.config.subtitle_format)
         table.add_row('subtitle_all', bool_str[self.config.subtitle_all])
@@ -782,6 +784,45 @@ def set_complete_audio_mix(self, text, line, start, finish):
 
     set_audio_mix.complete = set_complete_audio_mix
 
+    def set_audio_encoding(self, var, value):
+        """
+        This configuration option specifies the audio encoder. Validd values
+        are "av_aac", "fdk_aac", "fdk_haac", "mp3", "vorbis", "opus", "flac16",
+        "flac24", "ac3", and "eac3"
+        """
+        assert var == 'audio_encoding'
+        try:
+            value = {
+                'av-aac':   'av_aac',
+                'av_aac':   'av_aac',
+                'fdk-aac':  'fdk_aac',
+                'fdk_aac':  'fdk_aac',
+                'fdk-haac': 'fdk_haac',
+                'fdk_haac': 'fdk_haac',
+                'mp3':      'mp3',
+                'lame':     'mp3',
+                'vorbis':   'vorbis',
+                'opus':     'opus',
+                'flac':     'flac16',
+                'flac16':   'flac16',
+                'flac24':   'flac24',
+                'ac3':      'ac3',
+                'eac3':     'eac3',
+            }[value]
+        except KeyError:
+            raise CmdSyntaxError(f'Invalid audio encoding {value}')
+        else:
+            return var, value
+
+    def set_complete_audio_encoding(self, text, line, start, finish):
+        return self.set_complete_one(
+            line, start, {
+                'av-aac', 'av_aac', 'fdk-aac', 'fdk_aac', 'fdk-haac',
+                'fdk_haac', 'mp3', 'lame', 'vorbis', 'opus', 'flac', 'flac16',
+                'flac24', 'ac3', 'eac3'})
+
+    set_audio_encoding.complete = set_complete_audio_encoding
+
     def set_subtitle_format(self, var, value):
         """
         This configuration option specifies a subtitle format. Valid values

tvrip/ripper.py

@@ -303,7 +303,7 @@ def rip(self, config, episodes, title, audio_tracks, subtitle_tracks,
             # audio encoding options (use 160kbps FDK-AAC plus whatever downmix
             # the user selected for the specified tracks)
             '-a', ','.join(str(num)  for (num, _, _)  in audio_defs),
-            '-E', ','.join('fdk_aac' for ad           in audio_defs),
+            '-E', ','.join(config.audio_encoding for ad in audio_defs),
             '-B', ','.join('160'     for ad           in audio_defs),
             '-6', ','.join(mix       for (_, mix, _)  in audio_defs),
             '-A', ','.join(name      for (_, _, name) in audio_defs),

tvrip/var_audio_encoding.rst

@@ -0,0 +1 @@
+../docs/var_audio_encoding.rst