周末在網路上找到一個可下載 YT 影片 mp3 檔的網站 yt1ss.pro, 參考 :
但下載下來的 mp3 檔用 MP3Gain 去分析音軌時卻出現錯誤 :
我問 Gemini 原因, 它說這是因為 MP3Gain 只能處理標準的 MPEG Layer III (MP3) 音訊, 此下載的音檔雖然副檔名是 .mp3, 但其實際編碼格式是 MPEG Layer I, 這個非標準標籤會讓 MP3Gain 識別錯誤, 依照建議打開 "選項", 勾選 "不檢查層 I 或 II (N)" 選項 :
但這麼做似乎無效, 有些可以, 有些還是不行. 所以我改下載 MP4 檔, 然後再用 ffmpeg 從 mp4 中擷取音軌存成 mp3, 作法參考 :
例如陳瑞的情罪這首歌, 先下載 mp4 :
然後用下列指令擷取音軌直接存成 mp3 檔 :
ffmpeg -i 情罪_1080p.mp4 -vn -acodec libmp3lame -q:a 2 情罪_1080p.mp3
F:\mp3\新歌3>ffmpeg -i 情罪_1080p.mp4 -vn -acodec libmp3lame -q:a 2 情罪_1080p.mp3
ffmpeg version 2025-11-02-git-f5eb11a71d-essentials_build-www.gyan.dev Copyright (c) 2000-2025 the FFmpeg developers
built with gcc 15.2.0 (Rev8, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-cairo --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-libfreetype --enable-libfribidi --enable-libharfbuzz --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --enable-openal --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
libavutil 60. 16.100 / 60. 16.100
libavcodec 62. 19.100 / 62. 19.100
libavformat 62. 6.101 / 62. 6.101
libavdevice 62. 2.100 / 62. 2.100
libavfilter 11. 9.100 / 11. 9.100
libswscale 9. 3.100 / 9. 3.100
libswresample 6. 2.100 / 6. 2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '情罪_1080p.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf59.16.100
Duration: 00:04:45.49, start: 0.000000, bitrate: 219 kb/s
Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1080x1080 [SAR 1:1 DAR 1:1], 85 kb/s, 25 fps, 25 tbr, 12800 tbn (default)
Metadata:
handler_name : ISO Media file produced by Google Inc.
vendor_id : [0][0][0][0]
Stream #0:1[0x2](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : ISO Media file produced by Google Inc.
vendor_id : [0][0][0][0]
Stream mapping:
Stream #0:1 -> #0:0 (aac (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
Output #0, mp3, to '情罪_1080p.mp3':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
TSSE : Lavf62.6.101
Stream #0:0(und): Audio: mp3, 44100 Hz, stereo, fltp (default)
Metadata:
encoder : Lavc62.19.100 libmp3lame
handler_name : ISO Media file produced by Google Inc.
vendor_id : [0][0][0][0]
[out#0/mp3 @ 000001e1a6fc2040] video:0KiB audio:6275KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: 0.005525%
size= 6276KiB time=00:04:45.48 bitrate= 180.1kbits/s speed=80.3x elapsed=0:00:03.55
擷取出來的 mp3 檔就能順利通過 MP3Gain 的檢查了.
