FFMPEG：我需要音頻通道7和8作爲視頻的主音軌

Question

我有一個帶有8個通道音頻的視頻。

我需要軌道7（左立體聲）和8（右立體聲）作爲視頻（我正在轉換爲FLV）的音頻。

我試着-filter_complex和join，amix，並且amerge過濾器，還有-map參數打，但我似乎無法找到值的正確組合： -/

輸出：

/usr/local/bin/ffmpeg-1.0/bin/ffmpeg -i '/folder/video_name.mov' -f 'flv' \ 
-s '320x240' -b '250k' -aspect '4:3' -ac 1 -ab '64k' -ar '22050' -y \ 
/folder/video_name.flv 

ffmpeg version N-46241-g09ea482 Copyright (c) 2000-2012 the FFmpeg developers 
    built on Nov 5 2012 07:33:09 with gcc 4.1.2 (GCC) 20080704 (Red Hat 4.1.2-46) 
    configuration: --prefix=/usr/local/bin/ffmpeg-1.0 
    libavutil  52. 1.100/52. 1.100 
    libavcodec  54. 70.100/54. 70.100 
    libavformat 54. 35.100/54. 35.100 
    libavdevice 54. 3.100/54. 3.100 
    libavfilter  3. 21.105/3. 21.105 
    libswscale  2. 1.101/2. 1.101 
    libswresample 0. 16.100/0. 16.100 
Guessed Channel Layout for Input Stream #0.1 : mono 
Guessed Channel Layout for Input Stream #0.2 : mono 
Guessed Channel Layout for Input Stream #0.3 : mono 
Guessed Channel Layout for Input Stream #0.4 : mono 
Guessed Channel Layout for Input Stream #0.5 : mono 
Guessed Channel Layout for Input Stream #0.6 : mono 
Guessed Channel Layout for Input Stream #0.7 : mono 
Guessed Channel Layout for Input Stream #0.8 : mono 
Guessed Channel Layout for Input Stream #0.9 : mono 
Guessed Channel Layout for Input Stream #0.10 : mono 
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/folder/video_name.mov': 
    Metadata: 
    major_brand  : qt 
    minor_version : 537199360 
    compatible_brands: qt 
    creation_time : 2013-04-03 19:45:26 
    Duration: 00:00:39.03, start: 0.000000, bitrate: 122149 kb/s 
    Stream #0:0(eng): Video: prores (apch/0x68637061), yuv422p10le, 1920x1080, 110585 kb/s, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 23976 tbn, 23976 tbc 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
     timecode  : 00:59:53:00 
    Stream #0:1(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:2(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:3(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:4(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:5(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:6(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:7(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:8(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:9(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:10(eng): Audio: pcm_s24le (in24/0x34326E69), 48000 Hz, mono, s32, 1152 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
    Stream #0:11(eng): Data: none (tmcd/0x64636D74) 
    Metadata: 
     creation_time : 2013-04-03 19:45:30 
     handler_name : Apple Alias Data Handler 
     timecode  : 00:59:53:00 
Please use -b:a or -b:v, -b is ambiguous 
Output #0, flv, to '/folder/video_name.flv': 
    Metadata: 
    major_brand  : qt 
    minor_version : 537199360 
    compatible_brands: qt 
    encoder   : Lavf54.35.100 
    Stream #0:0(eng): Video: flv1 ([2][0][0][0]/0x0002), yuv420p, 320x240 [SAR 1:1 DAR 4:3], q=2-31, 250 kb/s, 1k tbn, 23.98 tbc 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
     timecode  : 00:59:53:00 
    Stream #0:1(eng): Audio: adpcm_swf ([1][0][0][0]/0x0001), 22050 Hz, mono, s16, 88 kb/s 
    Metadata: 
     creation_time : 2013-04-03 19:45:26 
     handler_name : Apple Alias Data Handler 
Stream mapping: 
    Stream #0:0 -> #0:0 (prores -> flv) 
    Stream #0:1 -> #0:1 (pcm_s24le -> adpcm_swf) 
Press [q] to stop, [?] for help 
frame= 33 fps=0.0 q=2.0 size=  108kB time=00:00:01.99 bitrate= 442.4kbits/s  
frame= 66 fps= 65 q=2.0 size=  225kB time=00:00:02.97 bitrate= 619.0kbits/s  
frame= 99 fps= 65 q=2.0 size=  341kB time=00:00:04.96 bitrate= 561.8kbits/s  
frame= 136 fps= 67 q=2.0 size=  400kB time=00:00:05.99 bitrate= 547.5kbits/s  
frame= 177 fps= 70 q=3.0 size=  482kB time=00:00:07.98 bitrate= 494.3kbits/s  
frame= 210 fps= 69 q=3.7 size=  590kB time=00:00:08.96 bitrate= 539.7kbits/s  
frame= 240 fps= 68 q=6.3 size=  660kB time=00:00:10.01 bitrate= 539.7kbits/s  
frame= 264 fps= 65 q=6.7 size=  719kB time=00:00:11.01 bitrate= 535.2kbits/s  
frame= 288 fps= 63 q=8.4 size=  772kB time=00:00:12.02 bitrate= 526.1kbits/s  
frame= 312 fps= 62 q=15.4 size=  829kB time=00:00:13.65 bitrate= 497.4kbits/s  
frame= 336 fps= 60 q=10.4 size=  875kB time=00:00:14.02 bitrate= 511.1kbits/s  
frame= 360 fps= 59 q=10.6 size=  916kB time=00:00:15.01 bitrate= 499.9kbits/s  
frame= 383 fps= 58 q=17.8 size=  957kB time=00:00:15.97 bitrate= 490.6kbits/s  
frame= 411 fps= 58 q=6.5 size= 1008kB time=00:00:17.97 bitrate= 459.3kbits/s  
frame= 437 fps= 57 q=9.7 size= 1046kB time=00:00:18.99 bitrate= 451.3kbits/s  
frame= 460 fps= 57 q=7.7 size= 1086kB time=00:00:20.01 bitrate= 444.6kbits/s  
frame= 489 fps= 57 q=11.3 size= 1144kB time=00:00:20.99 bitrate= 446.3kbits/s  
frame= 512 fps= 56 q=10.3 size= 1182kB time=00:00:22.01 bitrate= 439.8kbits/s  
frame= 535 fps= 55 q=21.5 size= 1225kB time=00:00:22.98 bitrate= 436.7kbits/s  
frame= 564 fps= 55 q=18.3 size= 1280kB time=00:00:24.00 bitrate= 436.8kbits/s  
frame= 587 fps= 55 q=8.5 size= 1311kB time=00:00:24.98 bitrate= 429.7kbits/s  
frame= 610 fps= 54 q=11.9 size= 1349kB time=00:00:26.00 bitrate= 424.9kbits/s  
frame= 636 fps= 54 q=7.5 size= 1383kB time=00:00:26.98 bitrate= 419.8kbits/s  
frame= 659 fps= 54 q=9.6 size= 1421kB time=00:00:28.00 bitrate= 415.6kbits/s  
frame= 683 fps= 54 q=20.0 size= 1471kB time=00:00:29.02 bitrate= 415.1kbits/s  
frame= 711 fps= 54 q=6.4 size= 1518kB time=00:00:30.00 bitrate= 414.5kbits/s  
frame= 742 fps= 54 q=6.2 size= 1558kB time=00:00:31.02 bitrate= 411.5kbits/s  
frame= 774 fps= 54 q=2.5 size= 1601kB time=00:00:33.01 bitrate= 397.1kbits/s  
frame= 816 fps= 55 q=2.0 size= 1632kB time=00:00:34.50 bitrate= 387.6kbits/s  
frame= 861 fps= 56 q=2.0 size= 1670kB time=00:00:35.99 bitrate= 380.1kbits/s  
frame= 905 fps= 57 q=2.0 size= 1706kB time=00:00:38.03 bitrate= 367.4kbits/s  
frame= 936 fps= 58 q=2.0 Lsize= 1730kB time=00:00:39.05 bitrate= 362.8kbits/s 
video:1278kB audio:423kB subtitle:0 global headers:0kB muxing overhead 1.654557% 

Answer 1

你在正確的軌道上amerge。

ffmpeg -i input -filter_complex "scale=320:-1;[0:7][0:8]amerge" -codec:v libx264 \ 
-preset medium -crf 23 -codec:a libmp3lame -q:a 5 -ar 44100 output.flv 

我建議使用libx264編碼H.264視頻，因爲這將提供每比特率更高的質量相比命名flv編碼器（即輸出FLV /索倫森火花/索倫森H.263編碼器）。 FLV容器可以使用H.264視頻。

我也建議使用libmp3lame來編碼音頻，否則你會得到蹩腳的舊adpcm_swf。

您的版本尚未配置爲支持這些外部編碼庫，但有static builds包含這些。

另見：

• FFmpeg Wiki: x264 Encoding Guide
• FFmpeg Wiki: MP3 Encoding Guide