我使用-sameq參數(相同質量)轉換AVI爲FLV與ffmpeg的:的ffmpeg:AVI爲FLV轉換雙打文件大小
ffmpeg -i test.avi -sameq -f flv sameq.flv
生成的文件具有相同的視頻和音頻質量與原始,但它是原始文件大小的兩倍以上:
84M sameq.flv
41M test.avi
爲什麼會發生?
轉換器輸出:
ffmpeg version N-34750-g070d2d7, Copyright (c) 2000-2011 the FFmpeg developers
built on Nov 12 2011 11:23:07 with gcc 4.6.1
configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-x11grab
libavutil 51. 24. 1/51. 24. 1
libavcodec 53. 33. 0/53. 33. 0
libavformat 53. 20. 0/53. 20. 0
libavdevice 53. 4. 0/53. 4. 0
libavfilter 2. 48. 0/2. 48. 0
libswscale 2. 1. 0/2. 1. 0
libpostproc 51. 2. 0/51. 2. 0
Input #0, avi, from 'test.avi':
Duration: 00:06:30.00, start: 0.000000, bitrate: 866 kb/s
Stream #0:0: Video: mpeg4 (Advanced Real Time Simple Profile) (DIVX/0x58564944), yuv420p, 400x300 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
Stream #0:1: Audio: mp3 (U[0][0][0]/0x0055), 44100 Hz, mono, s16, 64 kb/s
[buffer @ 0xa247ae0] w:400 h:300 pixfmt:yuv420p tb:1/1000000 sar:1/1 sws_param:
Output #0, flv, to 'sameq.flv':
Metadata:
encoder : Lavf53.20.0
Stream #0:0: Video: flv1 ([2][0][0][0]/0x0002), yuv420p, 400x300 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 1k tbn, 25 tbc
Stream #0:1: Audio: mp3 ([2][0][0][0]/0x0002), 44100 Hz, mono, s16, 128 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (mpeg4 -> flv)
Stream #0:1 -> #0:1 (mp3 -> libmp3lame)
Press [q] to stop, [?] for help
frame= 9742 fps=255 q=0.0 Lsize= 85074kB time=00:06:30.00 bitrate=1787.0kbits/s
video:79163kB audio:5525kB global headers:0kB muxing overhead 0.455568%
謝謝!偉大的建議!但爲什麼它在規模上翻倍還不清楚。 – weekens
原始使用mpeg4,通常比非h.264編解碼器具有更高的[壓縮比](http://www.kanecomputing.co.uk/pdfs/compression_ratio_rules_of_thumb.pdf),在您的情況下使用flv默認設置。 –