几年前，我使用了以下Bash脚本，从多个MP3文件和一张图片中提取视频（使视频中的图像在整个MP3长度上保持不变），这个脚本运行良好。
i=0;
for file in *.mp3;
do
i=$((i+1));
ffmpeg -loop 1 -shortest -y -i image.jpg -i $file -acodec copy -vcodec libx264 $file.flv;
done
现在我想再次使用它来做同样的事情。
问题：
它不会在mp3结尾处停止转换。这意味着当前的mp3文件长度为3分钟，但脚本会一直转换，除非我手动停止它，因此生成的flv文件长度比3分钟要大得多。
(已安装ffmpeg，但使用libav时情况相同)
输出：
ffmpeg version 1.2.6-7:1.2.6-1~trusty1 Copyright (c) 2000-2014 the FFmpeg developers
built on Apr 26 2014 18:52:58 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
configuration: --arch=amd64 --disable-stripping --enable-avresample --enable-pthreads --enable-runtime-cpudetect --extra-version='7:1.2.6-1~trusty1' --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --enable-bzlib --enable-libdc1394 --enable-libfreetype --enable-frei0r --enable-gnutls --enable-libgsm --enable-libmp3lame --enable-librtmp --enable-libopencv --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-vaapi --enable-vdpau --enable-libvorbis --enable-libvpx --enable-zlib --enable-gpl --enable-postproc --enable-libcdio --enable-x11grab --enable-libx264 --shlibdir=/usr/lib/x86_64-linux-gnu --enable-shared --disable-static
libavutil 52. 18.100 / 52. 18.100
libavcodec 54. 92.100 / 54. 92.100
libavformat 54. 63.104 / 54. 63.104
libavdevice 53. 5.103 / 53. 5.103
libavfilter 3. 42.103 / 3. 42.103
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[image2 @ 0x6d0740] max_analyze_duration 5000000 reached at 5000000 microseconds
Input #0, image2, from 'Bild2.png':
Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
Stream #0:0: Video: png, rgba, 382x417, 25 fps, 25 tbr, 25 tbn, 25 tbc
[mp3 @ 0x6c4ac0] max_analyze_duration 5000000 reached at 5015510 microseconds
[mp3 @ 0x6c4ac0] Estimating duration from bitrate, this may be inaccurate
Input #1, mp3, from 'sons.mp3':
Duration: 00:00:35.11, start: 0.000000, bitrate: 127 kb/s
Stream #1:0: Audio: mp3, 44100 Hz, stereo, s16p, 128 kb/s
[libx264 @ 0x6da700] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x6da700] profile High 4:4:4 Predictive, level 2.1, 4:4:4 8-bit
[libx264 @ 0x6da700] 264 - core 142 r2389 956c8d8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - 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=4 threads=6 lookahead_threads=1 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
Output #0, flv, to 'sons.mp3.flv':
Metadata:
encoder : Lavf54.63.104
Stream #0:0: Video: h264 ([7][0][0][0] / 0x0007), yuv444p, 382x417, q=-1--1, 1k tbn, 25 tbc
Stream #0:1: Audio: mp3 ([2][0][0][0] / 0x0002), 44100 Hz, stereo, 128 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (png -> libx264)
Stream #1:0 -> #0:1 (copy)
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