想问下什么指令能提取flac文件

[Magicicesea]

我看到音频源里有flac但是自己试了几个指令都不能直接下载flac而是生成了m4a格式的文件。

我试的指令如下

C:\bbdown> ~.\BBDown.exe https://www.bilibili.com/video/BV1Ld4y1M7bq/ bv --audio-only --encoding-priority flac
BBDown version 1.5.4, Bilibili Downloader.
欢迎到讨论区交流：
https://github.com/nilaoda/BBDown/discussions

[2022-12-19 02:04:14.009] - 加载本地cookie...
[2022-12-19 02:04:14.010] - 检测账号登录...
[2022-12-19 02:04:14.464] - 获取aid...
[2022-12-19 02:04:15.175] - 获取aid结束: 345853251
[2022-12-19 02:04:15.176] - 获取视频信息...
[2022-12-19 02:04:15.425] - 视频标题: [4K 60帧] 方大同 -《危险世界》超清修复 Hi-Res无损音质
[2022-12-19 02:04:15.425] - 发布时间: 09/22/2022 09:57:33
[2022-12-19 02:04:15.426] - P1: [840566773] [[4K 60帧] 方大同 -《危险世界》超清修复 Hi-Res无损音质] [07m30s]
[2022-12-19 02:04:15.426] - 共计 1 个分P, 已选择：ALL
[2022-12-19 02:04:15.426] - 开始解析P1...
[2022-12-19 02:04:16.469] - 共计4条音频流.
                            0. [FLAC] [2128 kbps] [~116.89 MB]
                            1. [M4A] [329 kbps] [~18.07 MB]
                            2. [M4A] [132 kbps] [~7.25 MB]
                            3. [M4A] [67 kbps] [~3.68 MB]
[2022-12-19 02:04:16.471] - 已选择的流:
                            [音频] [FLAC] [2128 kbps] [~116.63 MB]
[2022-12-19 02:04:16.472] - 开始多线程下载P1音频...
[2022-12-19 02:04:16.505] - 合并音频分片...
[2022-12-19 02:04:16.505] - 清理分片...
[2022-12-19 02:04:16.505] - 下载P1完毕
[2022-12-19 02:04:16.506] - 开始合并音视频...
[2022-12-19 02:04:16.521] - [mp4 @ 0000027355217640] track 0: codec frame size is not set
[2022-12-19 02:04:16.618] - 清理临时文件...
[2022-12-19 02:04:16.840] - 任务完成

PS C:\bbdown> .\BBDown.exe https://www.bilibili.com/video/BV1Ld4y1M7bq/ bv --audio-only --skip-mux
BBDown version 1.5.4, Bilibili Downloader.
欢迎到讨论区交流：
https://github.com/nilaoda/BBDown/discussions

[2022-12-19 02:08:28.872] - 加载本地cookie...
[2022-12-19 02:08:28.873] - 检测账号登录...
[2022-12-19 02:08:29.329] - 获取aid...
[2022-12-19 02:08:30.055] - 获取aid结束: 345853251
[2022-12-19 02:08:30.055] - 获取视频信息...
[2022-12-19 02:08:30.330] - 视频标题: [4K 60帧] 方大同 -《危险世界》超清修复 Hi-Res无损音质
[2022-12-19 02:08:30.330] - 发布时间: 09/22/2022 09:57:33
[2022-12-19 02:08:30.331] - P1: [840566773] [[4K 60帧] 方大同 -《危险世界》超清修复 Hi-Res无损音质] [07m30s]
[2022-12-19 02:08:30.331] - 共计 1 个分P, 已选择：ALL
[2022-12-19 02:08:30.331] - 开始解析P1...
[2022-12-19 02:08:30.654] - 下载封面...
[2022-12-19 02:08:31.633] - 共计4条音频流.
                            0. [FLAC] [2128 kbps] [~116.89 MB]
                            1. [M4A] [329 kbps] [~18.07 MB]
                            2. [M4A] [132 kbps] [~7.25 MB]
                            3. [M4A] [67 kbps] [~3.68 MB]
[2022-12-19 02:08:31.635] - 已选择的流:
                            [音频] [FLAC] [2128 kbps] [~116.63 MB]
[2022-12-19 02:08:31.636] - 开始多线程下载P1音频...
[2022-12-19 02:08:39.591] - 合并音频分片...
[2022-12-19 02:08:39.645] - 清理分片...
[2022-12-19 02:08:39.653] - 下载P1完毕
[2022-12-19 02:08:39.653] - 任务完成

如果可以麻烦大佬直接提供个command，感谢了！

[nilaoda]

ffmpeg -i i.m4a -c copy o.flac

[Magicicesea]

再提供一个方法，可以用FFmpeg Batch AV Converter, 然后在预设(presets)中有音频转换为FLAC通道。是GUI界面，且可以批量操作，小白操作起来比较方便。