我正在使用以下 ffmpeg 命令在现有视频文件中添加背景音乐 mp3 文件
ffmpeg \
-i ./output/output.mp4 \
-i ./output/audio-loop.mp3 \
-filter_complex \
"[0:a]apad[main]; \
[1:a]volume=-31dB,apad[A]; \
[main][A]amerge[out]" \
-c:v libx264 -c:a aac -map 0:v -map "[out]" \
-ac 2 -shortest -y ./output/new_output.mp4
除视频文件持续时间外，上述命令一切正常。
该文件的时长output.mp4为1分30秒。
运行上述命令时，new_output.mp4文件持续时间与原始文件不一样，1:27 seconds但原始文件持续时间为1:30秒。
audio-loop.mp3文件时长为3:16 seconds
请帮忙
Complete Logs
ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
built with Apple clang version 12.0.0 (clang-1200.0.32.29)
configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/4.3.1_9 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './output/output.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.45.100
Duration: 00:01:29.84, start: 0.000000, bitrate: 564 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1280x720, 479 kb/s, 30 fps, 30 tbr, 12k tbn, 60 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 24000 Hz, mono, fltp, 93 kb/s (default)
Metadata:
handler_name : SoundHandler
Input #1, mp3, from './output/audio-loop.mp3':
Duration: 00:03:16.26, start: 0.025057, bitrate: 192 kb/s
Stream #1:0: Audio: mp3, 44100 Hz, stereo, fltp, 192 kb/s
Metadata:
encoder : LAME3.97
Side data:
replaygain: track gain - -5.700000, track peak - unknown, album gain - unknown, album peak - unknown,
Stream mapping:
Stream #0:1 (aac) -> apad (graph 0)
Stream #1:0 (mp3float) -> volume (graph 0)
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
amerge (graph 0) -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[libx264 @ 0x14300d800] using cpu capabilities: ARMv8 NEON
[libx264 @ 0x14300d800] profile High, level 3.1, 4:2:0, 8-bit
[libx264 @ 0x14300d800] 264 - core 161 r3043 59c0609 - H.264/MPEG-4 AVC codec - Copyleft 2003-2021 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[Parsed_amerge_3 @ 0x140f17dd0] No channel layout for input 1
Output #0, mp4, to './output/new_output.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.45.100
Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 1280x720, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
Metadata:
handler_name : VideoHandler
encoder : Lavc58.91.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 24000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
encoder : Lavc58.91.100 aac
frame= 2611 fps=532 q=-1.0 Lsize= 2002kB time=00:01:27.04 bitrate= 188.4kbits/s speed=17.7x
video:567kB audio:1366kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 3.577758%
[libx264 @ 0x14300d800] frame I:11 Avg QP:18.32 size: 23236
[libx264 @ 0x14300d800] frame P:683 Avg QP:23.17 size: 282
[libx264 @ 0x14300d800] frame B:1917 Avg QP:33.29 size: 68
[libx264 @ 0x14300d800] consecutive B-frames: 1.2% 2.7% 0.2% 95.9%
[libx264 @ 0x14300d800] mb I I16..4: 7.9% 81.2% 10.9%
[libx264 @ 0x14300d800] mb P I16..4: 0.0% 0.1% 0.0% P16..4: 0.3% 0.0% 0.1% 0.0% 0.0% skip:99.5%
[libx264 @ 0x14300d800] mb B I16..4: 0.0% 0.1% 0.0% B16..8: 0.5% 0.0% 0.0% direct: 0.0% skip:99.4% L0:45.4% L1:54.1% BI: 0.5%
[libx264 @ 0x14300d800] 8x8 transform intra:83.3% inter:33.5%
[libx264 @ 0x14300d800] coded y,uvDC,uvAC intra: 6.7% 6.0% 5.8% inter: 0.1% 0.0% 0.0%
[libx264 @ 0x14300d800] i16 v,h,dc,p: 74% 22% 3% 0%
[libx264 @ 0x14300d800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 68% 4% 27% 0% 0% 0% 0% 0% 0%
[libx264 @ 0x14300d800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 47% 22% 9% 2% 3% 6% 5% 3% 3%
[libx264 @ 0x14300d800] i8c dc,h,v,p: 88% 8% 3% 0%
[libx264 @ 0x14300d800] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x14300d800] ref P L0: 72.1% 24.6% 2.2% 1.1%
[libx264 @ 0x14300d800] ref B L0: 72.3% 26.8% 0.9%
[libx264 @ 0x14300d800] ref B L1: 99.1% 0.9%
[libx264 @ 0x14300d800] kb/s:53.27
[aac @ 0x143010800] Qavg: 964.117