您好我在Redhat5上构建了ffmpeg可执行文件。我想使用命令multiple混合两个Audio “ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix = inputs = 3：duration = first：dropout_transition = 3 OUTPUT.mp3”。
我启用了libflamemp3库而没有任何错误。
[root@localhost ~]# ffmpeg -i /root/media/Katlalli.mp3 -i /root/media/Katlalli.mp3 -filter_complex amix=inputs=2:duration=first:dropout_transition=2 /root/media/OUTPutnew123.mp3
ffmpeg version 2.1 Copyright (c) 2000-2013 the FFmpeg developers
built on Nov 14 2013 03:17:10 with gcc 4.1.2 (GCC) 20080704 (Red Hat 4.1.2-46)
configuration: --enable-libmp3lame
libavutil 52. 48.100 / 52. 48.100
libavcodec 55. 39.100 / 55. 39.100
libavformat 55. 19.104 / 55. 19.104
libavdevice 55. 5.100 / 55. 5.100
libavfilter 3. 90.100 / 3. 90.100
libswscale 2. 5.101 / 2. 5.101
libswresample 0. 17.104 / 0. 17.104
[mp3 @ 0x193ef240] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from '/root/media/Katlalli.mp3':
Metadata:
artist : Yograj Bhat
title : Katlalli Karadige
track : 3
album : Paramathma
album_artist : Puneet Rajkumar
genre : Kannada
composer : V.Harikrishna
date : 2011
Duration: 00:04:41.46, start: 0.000000, bitrate: 191 kb/s
Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
Stream #0:1: Video: mjpeg, yuvj420p(pc), 200x200 [SAR 96:96 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
Metadata:
title : thumbnail
comment : Cover (front)
[mp3 @ 0x194090a0] Estimating duration from bitrate, this may be inaccurate
Input #1, mp3, from '/root/media/Katlalli.mp3':
Metadata:
artist : Yograj Bhat
title : Katlalli Karadige
track : 3
album : Paramathma
album_artist : Puneet Rajkumar
genre : Kannada
composer : V.Harikrishna
date : 2011
Duration: 00:04:41.46, start: 0.000000, bitrate: 191 kb/s
Stream #1:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
Stream #1:1: Video: mjpeg, yuvj420p(pc), 200x200 [SAR 96:96 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
Metadata:
title : thumbnail
comment : Cover (front)
File '/root/media/OUTPutnew123.mp3' already exists. Overwrite ? [y/N] y
Output #0, mp3, to '/root/media/OUTPutnew123.mp3':
Metadata:
artist : Yograj Bhat
title : Katlalli Karadige
track : 3
album : Paramathma
album_artist : Puneet Rajkumar
genre : Kannada
composer : V.Harikrishna
date : 2011
Stream #0:0: Audio: mp3, 44100 Hz, stereo, fltp (default)
Stream #0:1: Video: none, q=2-31, 128 kb/s, 90k tbn
Metadata:
title : thumbnail
comment : Cover (front)
Stream mapping:
Stream #0:0 (mp3) -> amix:input0
Stream #1:0 (mp3) -> amix:input1
amix -> Stream #0:0 (libmp3lame)
Stream #0:1 -> #0:1 (mjpeg -> ?)
Encoder (codec none) not found for output stream #0:1
但是当我尝试组合两个mp3音频时， “ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix = inputs = 3：duration = first：dropout_transition = 3 OUTPUT.mp3”。
我收到错误
“输出流＃0：1”
找不到“编码器（编解码器无）”所以请帮我看看如何在Redhat5上链接或安装“libmp3flame”。
答案 0 :(得分：2)
我相信ffmpeg正在尝试解码PNG输入视频流（专辑封面）并将输出视频流编码为PNG输出，但我假设您构建的ffmpeg没有zlib支持，这是PNG编码和解码所必需的。
如果可用，会自动检测zlib，因此您需要在ffmpeg编译之前安装zlib标头（Red Hat＆n; n朋友的zlib-devel包）。
或者，您可以保留构建并告诉ffmpeg忽略任何带有-vn输出选项的视频。
mjpeg 如果您想保留构建并保留专辑封面，请添加-codec:v mjpeg作为输出选项。请参阅stream selection，了解ffmpeg将选择哪两个输入。
-codec:v copy 您还可以使用-codec:v copy stream copy视频。这可能比使用-codec:v mjpeg重新编码更可取。请参阅stream selection以了解ffmpeg将选择哪两个输入。如果您添加-map 0 -map 1，则会包含两个视频流。