Seguindo link Estou usando o seguinte para mesclar um arquivo de áudio e vídeo em um arquivo com um pan de áudio personalizado regras.
ffmpeg -i vid.mp4 -i rec.mp3 -filter_complex "[0:a][1:a]amerge[a]" \
-strict experimental -c:a aac -map 0:v -map "[a]" -ar 48000 -ab 128k \
-c:v copy -f mp4 out.mp4 -y
ffmpeg version N-61286-gdbc3e11 Copyright (c) 2000-2014 the FFmpeg developers
built on Mar 11 2014 22:01:37 with gcc 4.8.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-zlib
libavutil 52. 66.101 / 52. 66.101
libavcodec 55. 52.102 / 55. 52.102
libavformat 55. 34.100 / 55. 34.100
libavdevice 55. 11.100 / 55. 11.100
libavfilter 4. 3.100 / 4. 3.100
libswscale 2. 5.101 / 2. 5.101
libswresample 0. 18.100 / 0. 18.100
libpostproc 52. 3.100 / 52. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'vid.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf55.34.100
Duration: 00:00:20.07, start: 0.033333, bitrate: 214 kb/s
Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 480x270 [SAR 1:1 DAR 16:9], 80 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
[mp3 @ 02c6c2a0] Estimating duration from bitrate, this may be inaccurate
Input #1, mp3, from 'rec.mp3':
Duration: 00:00:50.31, start: 0.000000, bitrate: 127 kb/s
Stream #1:0: Audio: mp3, 44100 Hz, mono, s16p, 128 kb/s
[Parsed_amerge_0 @ 02d514e0] No channel layout for input 1
[Parsed_amerge_0 @ 02d514e0] Input channel layouts overlap: output layout will be determined by the number of distinct input channels
Output #0, mp4, to 'out.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf55.34.100
Stream #0:0(eng): Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 480x270 [SAR 1:1 DAR 16:9], q=2-31, 80 kb/s, 25 fps, 12800 tbn, 12800 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1: Audio: aac ([64][0][0][0] / 0x0040), 48000 Hz, stereo, fltp, 128 kb/s (default)
Stream mapping:
Stream #0:1 (aac) -> amerge:in0
Stream #1:0 (mp3) -> amerge:in1
Stream #0:0 -> #0:0 (copy)
amerge -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[mp3 @ 02c6f960] overread, skip -6 enddists: -4 -4
frame= 501 fps=227 q=-1.0 Lsize= 527kB time=00:00:20.07 bitrate= 215.0kbits/s
video:196kB audio:315kB subtitle:0 data:0 global headers:0kB muxing overhead 3.170177%
O problema é que, se o vídeo tiver 30 segundos e o áudio 45, o vídeo final será 30 segundos, por isso, faltam os 15 segundos restantes de áudio. Exibir apenas uma tela preta ou o quadro final do vídeo pelos segundos restantes (até o áudio terminar) ficará bem.
Como posso fazer isso?
Depois de fazer alguns testes, parece que o problema é causado pelo filtro amerge . Segundo a documentação:
6.7 amerge
[...]
If inputs do not have the same duration, the output will stop with the shortest.
Tente usar apad como um filtro anterior:
ffmpeg -i vid.mp4 -i rec.mp3 -filter_complex \
"[0:a]apad [b] ; [b][1:a]amerge[a]" \
-strict experimental -c:a aac -map 0:v -map "[a]" -ar 48000 -ab 128k \
-c:v copy -f mp4 out.mp4 -y
Tags ffmpeg