Repository: yt-dlp/yt-dlp
File: yt_dlp/extractor/jiosaavn.py (Python)

Code before:
            'init json', audio_id, transform_source=js_to_json)


class JioSaavnSongIE(JioSaavnBaseIE):
    _VALID_URL = r'https?://(?:www\.)?(?:jiosaavn\.com/song/[^/?#]+/|saavn\.com/s/song/(?:[^/?#]+/){3})(?P<id>[^/?#]+)'
    _TESTS = [{
        'url': 'https://www.jiosaavn.com/song/leja-re/OQsEfQFVUXk',
        'md5': '7b1f70de088ede3a152ea34aece4df42',
        'info_dict': {
            'id': 'OQsEfQFVUXk',
            'ext': 'mp3',
            'title': 'Leja Re',
            'album': 'Leja Re',
            'thumbnail': 'https://c.saavncdn.com/258/Leja-Re-Hindi-2018-20181124024539-500x500.jpg',
        },
    }, {
        'url': 'https://www.saavn.com/s/song/hindi/Saathiya/O-Humdum-Suniyo-Re/KAMiazoCblU',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        audio_id = self._match_id(url)
        song_data = self._extract_initial_data(url, audio_id)['song']['song']
        formats = []
        # available bitrates are 16, 32, 64, 128, 320
        for bitrate in self._configuration_arg('bitrate', ['16', '32', '64', '128', '320'], ie_key='JioSaavn'):
            media_data = self._download_json(
                'https://www.jiosaavn.com/api.php', audio_id, f'Downloading format info for {bitrate}',
                fatal=False, data=urlencode_postdata({
                    '__call': 'song.generateAuthToken',
                    '_format': 'json',
                    'bitrate': bitrate,
                    'url': song_data['encrypted_media_url'],
                }))
            if not media_data.get('auth_url'):
                self.report_warning(f'Unable to extract format info for {bitrate}')
                continue
            formats.append({
                'url': media_data['auth_url'],
                'ext': media_data.get('type'),
                'id': bitrate,
                'format_id': bitrate,
                'abr': int(bitrate),
                'vcodec': 'none',
                'acodec': media_data.get('type'),
                **traverse_obj(song_data, {
                    'title': ('title', 'text'),
                    'album': ('album', 'text'),
                    'thumbnail': ('image', 0, {url_or_none}),
                }),
            })

Review comment (refactor):
The idea here was that we don't request all bitrates in order to speed up downloading, and instead allow the user to extract additional formats if they so desire. I would also add a check to see if the provided bitrate was valid (the server returns a file, regardless of what you request) and change the order:
```suggestion
        extract_bitrates = self._configuration_arg('bitrate', ['128', '320'], ie_key='JioSaavn')
        if not all(bitrate in ('16', '32', '64', '128', '320') for bitrate in extract_bitrates):
            raise ValueError(f'Invalid bitrate(s) {extract_bitrates}')

        song_data = self._extract_initial_data(url, audio_id)['song']['song']
        formats = []
        for bitrate in extract_bitrates:
```
Please also document this extractor arg in the readme.

Code after:
            r'window\.__INITIAL_DATA__\s*=', webpage,
            'init json', audio_id, transform_source=js_to_json)


class JioSaavnSongIE(JioSaavnBaseIE):
    _VALID_URL = r'https?://(?:www\.)?(?:jiosaavn\.com/song/[^/?#]+/|saavn\.com/s/song/(?:[^/?#]+/){3})(?P<id>[^/?#]+)'
    _TESTS = [{
        'url': 'https://www.jiosaavn.com/song/leja-re/OQsEfQFVUXk',
        'md5': '3b84396d15ed9e083c3106f1fa589c04',
        'info_dict': {
            'id': 'OQsEfQFVUXk',
            'ext': 'mp4',
            'title': 'Leja Re',
            'album': 'Leja Re',
            'thumbnail': 'https://c.saavncdn.com/258/Leja-Re-Hindi-2018-20181124024539-500x500.jpg',
            'duration': 205,
            'view_count': int,
            'release_year': 2018,
        },
    }, {
        'url': 'https://www.saavn.com/s/song/hindi/Saathiya/O-Humdum-Suniyo-Re/KAMiazoCblU',
        'only_matching': True,
    }]

    _VALID_BITRATES = ('16', '32', '64', '128', '320')

    def _real_extract(self, url):
        audio_id = self._match_id(url)
        extract_bitrates = self._configuration_arg('bitrate', ['128', '320'], ie_key='JioSaavn')
        if invalid_bitrates := [br for br in extract_bitrates if br not in self._VALID_BITRATES]:
            raise ValueError(
                f'Invalid bitrate(s): {", ".join(invalid_bitrates)}. '
                + f'Valid bitrates are: {", ".join(self._VALID_BITRATES)}')

        song_data = self._extract_initial_data(url, audio_id)['song']['song']
        formats = []
        for bitrate in extract_bitrates:
            media_data = self._download_json(
                'https://www.jiosaavn.com/api.php', audio_id, f'Downloading format info for {bitrate}',
                fatal=False, data=urlencode_postdata({
                    '__call': 'song.generateAuthToken',
                    '_format': 'json',
                    'bitrate': bitrate,
                    'url': song_data['encrypted_media_url'],
                }))
            if not media_data.get('auth_url'):
                self.report_warning(f'Unable to extract format info for {bitrate}')
                continue
            formats.append({
                'url': media_data['auth_url'],
                'ext': media_data.get('type'),