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• flv reencode to mp4 for iphone/ipod via ffmpeg and x264 (quality issue)

  3 octobre 2011, par zeroasterisk

  There are a lot of questions on this topic, and I've read most of them and most of the google search results I could come up with.

  When I use FFMPEG to convert a FLV to a iphone3 compatble MP4 file, it just doesn't preserver enough of the quality. Yes, I've worked the hell out of -sameq and -b and -bt settings, text just isn't readable.

  Next I tried to split the video out and process it directly, using these instructions :
  https://sites.google.com/site/linuxencoding/x264-encoding-guide

  The problem is myplayer (via ffmpeg) was not able to determine the duration of the FLV (even though the metadata was set).

  (I assume) Because of that unknown duration, when I create the MP4 file, the resulting x264 file plays through super-fast while the audio plays at the normal rate.

  user@server:/tmp# mplayer -nosound -benchmark -sws 9 -vf dsize=640:480:0,scale=0:0,expand=640:480 -vo yuv4mpeg:file=>(x264 --demuxer y4m --crf 0 --preset slow --threads auto --output output.264 - 2>x264.log) 'input.flv'
  
  MPlayer 1.0rc4-4.4.5 (C) 2000-2010 MPlayer Team
  
  mplayer: could not connect to socket
  
  mplayer: No such file or directory
  
  Failed to open LIRC support. You will not be able to use your remote control.
  
  
  
  Playing input.flv.
  
  libavformat file format detected.
  
  [flv @ 0x1202460]Estimating duration from bitrate, this may be inaccurate
  
  [lavf] stream 0: video (vp6f), -vid 0
  
  [lavf] stream 1: audio (nellymoser), -aid 0
  
  VIDEO:  [VP6F]  1680x992  0bpp  1000.000 fps   33.4 kbps ( 4.1 kbyte/s)
  
  Clip info:
  
   audiocodecid: 6
  
   audiodatarate: 86
  
   audiosamplerate: 44100
  
   audiosamplesize: 16
  
   audiosize: 6097005
  
   canSeekToEnd: true
  
   datasize: 8609138
  
   duration: 567
  
   framerate: 2
  
   hasAudio: true
  
   hasCuePoints: false
  
   hasKeyframes: true
  
   hasMetadata: true
  
   hasVideo: true
  
   height: 992
  
   lasttimestamp: 567
  
   metadatacreator: flvtool++ (Facebook, Motion project, dweatherford)
  
   stereo: false
  
   totalframes: 1043
  
   videocodecid: 4
  
   videodatarate: 33
  
   videosize: 2316256
  
   width: 1680
  
  Using (default) progressive frame mode.Opening video filter: [expand w=640 h=480]
  
  Expand: 640 x 480, -1 ; -1, osd: 0, aspect: 0.000000, round: 1
  
  Opening video filter: [scale w=0 h=0]
  
  Opening video filter: [dsize=640:480:0]
  
  ==========================================================================
  
  Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
  
  Selected video codec: [ffvp6f] vfm: ffmpeg (FFmpeg VP6 Flash)
  
  ==========================================================================
  
  Audio: no sound
  
  Starting playback...
  
  Movie-Aspect is undefined - no prescaling applied.
  
  [swscaler @ 0x7f0c738b9620]Lanczos scaler, from yuv420p to yuv420p using MMX2
  
  VO: [yuv4mpeg] 640x480 => 641x480 Planar YV12

  I have also tried specifying FPS, but no change in results

  user@server:/tmp# mplayer -nosound -fps 25-benchmark -sws 9 -vf dsize=640:480:0,scale=0:0,expand=640:480 -vo yuv4mpeg:file=>(x264 --demuxer y4m --fps 25 --crf 0 --preset slow --threads auto --output output.264 - 2>x264.log) 'input.flv'

  Can someone tell me how to either :

  1. fix my split A/V processing/timing/duration issues ?
  2. improve the
     quality of the FFMPEG conversion of FLV to iphone3 compatible
     format ?

• ffmpeg smooth video upscaling

  21 janvier 2013, par bbbonthemoon

  I've got some old videos in 320x240 that I want to upscale to 640x480

  DISCLAIMER : I know upscaling always ruins quality.

  My problem is that, "regular" upscaling options in ffmpeg(-s or scale filter) always give much worse results comparing to manual resizing in any media player when watching video(Resize 2:1 option in Ubuntu's Movie Player for example). So, it's clear that there are better algorithms, which are used by the player to upscale the video. I just dont know how ta make ffmpeg use them, I'm newbie video converter :-) I need your help with converting options for ffmpeg for smooth as possible upscale.
  Thanks in advance !

• audio extracted from flv file via ffmpeg is of shorter duration than the actual flv video [closed]

  11 janvier 2013, par user1961143

  I have extracted audio from flv file via ffmpeg using this command :-

  ffmpeg -i 164_29.flv v19.mp3

  The flv videos duration is 3 minutes but the audio is of 2 mins 20 seconds only. On searching i found that the silent pieces of audio are removed when generating audio from ffmpeg. But i need the audio file to be of exactly same duration as flv video as later i need to put this audio in the flv video itself. Please help as this is urgent for our project. I am running the FFMpeg via .net windows service, so in case you know any other tool which can extract the audio of same duration as video and can be run via .net, it would be useful too.

  Console output :

  C :\Users\ritika.thakur>ffmpeg -i 164_29.flv v19.mp3
  ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers
  built on Nov 25 2012 12:23:20 with gcc 4.7.2 (GCC)
  configuration : —disable-static —enable-shared —enable-gpl —enable-version —disable-pthreads —enable-runtime-cpudetect —enable-avisynth —enable-bzlib —enable-frei0r —enable-libass —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libfreetype —enable-libgsm —enable-libmp3lame —enable-libnut -enable-libopenjpeg —enable-libopus —enable-librtmp —enable-libschroedinger -enable-libspeex —enable-libtheora —enable-libutvideo —enable-libvo-aacenc —enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libx264 —enale-libxavs —enable-libxvid —enable-zlib
  libavutil 52. 9.100 / 52. 9.100
  libavcodec 54. 77.100 / 54. 77.100
  libavformat 54. 37.100 / 54. 37.100
  libavdevice 54. 3.100 / 54. 3.100
  libavfilter 3. 23.102 / 3. 23.102
  libswscale 2. 1.102 / 2. 1.102
  libswresample 0. 17.101 / 0. 17.101
  libpostproc 52. 2.100 / 52. 2.100
  Input #0, flv, from '164_29.flv' :
  Metadata :
  canSeekToEnd : false
  createdby : FMS 4.0
  creationdate : Tue Jan 08 00:26:19 2013
  Duration : 00:03:04.08, start : 0.000000, bitrate : 283
  kb/s
  Stream #0:0 : Video : flv1, yuv420p, 320x240, 1k tbr, 1k tbn, 1k tbc
  Stream #0:1 : Audio : nellymoser, 22050 Hz, mono, flt
  Output #0, mp3, to 'v19.mp3' :
  Metadata :
  canSeekToEnd : false
  createdby : FMS 4.0
  creationdate : Tue Jan 08 00:26:19 2013
  TSSE : Lavf54.37.100
  Stream #0:0 : Audio : mp3, 22050 Hz, mono, fltp
  Stream mapping :
  Stream #0:1 -> #0:0 (nellymoser -> libmp3lame)
  Press [q] to stop, [?] for help
  size= 567kB time=00:03:04.13 bitrate= 25.2kbits/s video:0kB audio:567kB subtitle:0 global headers:0kB muxing overhead 0.051503%

  This is the output of console for both video and audio file separately :-

  Microsoft Windows [Version 6.1.7601]
  Copyright (c) 2009 Microsoft Corporation. All rights reserved.

  C :\Users\ritika.thakur>ffmpeg -i v19.mp3

  ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers
  built on Nov 25 2012 12:23:20 with gcc 4.7.2 (GCC)
  configuration : —disable-static —enable-shared —enable-gpl —enable-version3
  —disable-pthreads —enable-runtime-cpudetect —enable-avisynth —enable-bzlib
  — enable-frei0r —enable-libass —enable-libopencore-amrnb —enable-libopencore-
  amrwb —enable-libfreetype —enable-libgsm —enable-libmp3lame —enable-libnut -
   enable-libopenjpeg —enable-libopus —enable-librtmp —enable-libschroedinger -
   enable-libspeex —enable-libtheora —enable-libutvideo —enable-libvo-aacenc —
  enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libx264 —enab
  le-libxavs —enable-libxvid —enable-zlib
  libavutil 52. 9.100 / 52. 9.100
  libavcodec 54. 77.100 / 54. 77.100
  libavformat 54. 37.100 / 54. 37.100
  libavdevice 54. 3.100 / 54. 3.100
  libavfilter 3. 23.102 / 3. 23.102
  libswscale 2. 1.102 / 2. 1.102
  libswresample 0. 17.101 / 0. 17.101
  libpostproc 52. 2.100 / 52. 2.100
  [mp3 @ 0056e780] max_analyze_duration 5000000 reached at 5015510
  Input #0, mp3, from 'v19.mp3' :
  Metadata :
  canSeekToEnd : false
  createdby : FMS 4.0
  creationdate : Tue Jan 08 00:26:19 2013
  encoder : Lavf54.37.100
  Duration : 00:02:25.14, start : 0.000000, bitrate : 32 kb/s
  Stream #0:0 : Audio : mp3, 22050 Hz, mono, s16, 32 kb/s
  At least one output file must be specified

  C :\Users\ritika.thakur>ffmpeg -i 164_29.flv

  ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers
  built on Nov 25 2012 12:23:20 with gcc 4.7.2 (GCC)
  configuration : —disable-static —enable-shared —enable-gpl —enable-version3
  —disable-pthreads —enable-runtime-cpudetect —enable-avisynth —enable-bzlib
  — enable-frei0r —enable-libass —enable-libopencore-amrnb —enable-libopencore-
  amrwb —enable-libfreetype —enable-libgsm —enable-libmp3lame —enable-libnut -
   enable-libopenjpeg —enable-libopus —enable-librtmp —enable-libschroedinger -
   enable-libspeex —enable-libtheora —enable-libutvideo —enable-libvo-aacenc —
  enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libx264 —enab
  le-libxavs —enable-libxvid —enable-zlib
  libavutil 52. 9.100 / 52. 9.100
  libavcodec 54. 77.100 / 54. 77.100
  libavformat 54. 37.100 / 54. 37.100
  libavdevice 54. 3.100 / 54. 3.100
  libavfilter 3. 23.102 / 3. 23.102
  libswscale 2. 1.102 / 2. 1.102
  libswresample 0. 17.101 / 0. 17.101
  libpostproc 52. 2.100 / 52. 2.100
  Input #0, flv, from '164_29.flv' :
  Metadata :
  canSeekToEnd : false
  createdby : FMS 4.0
  creationdate : Tue Jan 08 00:26:19 2013
  Duration : 00:03:04.08, start : 0.000000, bitrate : 283 kb/s
  Stream #0:0 : Video : flv1, yuv420p, 320x240, 1k tbr, 1k tbn, 1k tbc
  Stream #0:1 : Audio : nellymoser, 22050 Hz, mono, flt
  At least one output file must be specified

  If you see the duration of video is of 3:04 but audio extracted from it is of 2:25 only.
  Actually i am using ffmpeg overlay to show two videos side by side in our debate project for the client. Now ffmpeg takes audio from first video by default. But we want the audio from both videos together as a debate going on. Hence I thought of a solution to extract audio from both videos and merge them and than apply them to the overlayed video. This will all work perfectly only if I get the complete audio from the video file i.e. of equal duration.
  For more information i am writing here the overlay command we are using :-

   **ffmpeg -i 164_29.flv  -vf "[in] scale=359:320, pad=2*iw+6:ih
  
    [left];    movie=164_30.flv, scale=359:320 [right]; [left][right] 
  
    overlay=365:0  [out]" -b:v 3600k -y a1.flv**
  
  
  
   **This is the console output of this overlay command:-**

  C :\Users\ritika.thakur>ffmpeg -i 164_29.flv -vf "[in] scale=359:320, pad=2*iw+6
  :ih [left] ; movie=164_30.flv, scale=359:320 [right] ; [left][right] overlay=365:0
  [out]" -b:v 3600k -y a1.flv
  ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers
  built on Nov 25 2012 12:23:20 with gcc 4.7.2 (GCC)
  configuration : —disable-static —enable-shared —enable-gpl —enable-version3
  —disable- pthreads —enable-runtime-cpudetect —enable- avisynth
  —enable-bzlib —enable
  -frei0r
  —enable-libass —enable-libopencore-amrnb —enable-libopencore-amrwb
  —enable- libfreetype —enable-libgsm —enable-libmp3lame —enable-libnut
  —enable-libopenjpeg —enable-libopus —enable-librtmp —enable-libschroedinger
  — enable-
  libspeex —enable-libtheora —enable- libutvideo
  —enable-libvo-aacenc —
  enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx
  —enable-libx264 —enab
  le-libxavs —enable-libxvid —enable-zlib
  libavutil 52. 9.100 / 52. 9.100
  libavcodec 54. 77.100 / 54. 77.100
  libavformat 54. 37.100 / 54. 37.100
  libavdevice 54. 3.100 / 54. 3.100
  libavfilter 3. 23.102 / 3. 23.102
  libswscale 2. 1.102 / 2. 1.102
  libswresample 0. 17.101 / 0. 17.101
  libpostproc 52. 2.100 / 52. 2.100
  Input #0, flv, from '164_29.flv' :
  Metadata :
  canSeekToEnd : false
  createdby : FMS 4.0
  creationdate : Tue Jan 08 00:26:19 2013
  Duration : 00:03:04.08, start : 0.000000, bitrate : 283 kb/s
  Stream #0:0 : Video : flv1, yuv420p, 320x240, 1k tbr, 1k tbn, 1k tbc
  Stream #0:1 : Audio : nellymoser, 22050 Hz, mono, flt
  Output #0, flv, to 'a1.flv' :
  Metadata :
  canSeekToEnd : false
  createdby : FMS 4.0
  creationdate : Tue Jan 08 00:26:19 2013
  encoder : Lavf54.37.100
  Stream #0:0 : Video : flv1 ([2][0][0][0] / 0x0002), yuv420p, 724x320, q=2-31,
  3600 kb/s, 1k tbn, 1k tbc
  Stream #0:1 : Audio : mp3 ([2][0][0][0] / 0x0002), 22050 Hz, mono, fltp
  Stream mapping :
  Stream #0:0 -> #0:0 (flv -> flv)
  Stream #0:1 -> #0:1 (nellymoser -> libmp3lame)
  Press [q] to stop, [?] for help
  frame= 83 fps=0.0 q=4.1 size= 343kB time=00:00:07.01 bitrate= 401.2kbits/s
  frame= 149 fps=149 q=2.3 size= 861kB time=00:00:14.87 bitrate= 473.9kbits/s
  frame= 223 fps=148 q=2.0 size= 1492kB time=00:00:22.00 bitrate= 555.4kbits/s
  frame= 308 fps=153 q=2.0 size= 2195kB time=00:00:28.64 bitrate= 627.8kbits/s
  frame= 391 fps=156 q=2.0 size= 2858kB time=00:00:34.06 bitrate= 687.4kbits/s
  frame= 478 fps=159 q=2.0 size= 3541kB time=00:00:39.55 bitrate= 733.4kbits/s
  frame= 547 fps=156 q=2.0 size= 4293kB time=00:00:46.80 bitrate= 751.5kbits/s
  frame= 645 fps=161 q=2.0 size= 4896kB time=00:00:51.63 bitrate= 776.8kbits/s
  Buffer queue overflow, dropping.
  [Parsed_overlay_4 @ 0152ca80] Buffer queue overflow, dropping.
  Last message repeated 16 times
  frame= 731 fps=162 q=2.0 size= 5418kB time=00:00:56.61 bitrate= 784.0kbits/s
  Buffer queue overflow, dropping.
  [Parsed_overlay_4 @ 0152ca80] Buffer queue overflow, dropping.
  Last message repeated 49 times
  frame= 794 fps=158 q=2.0 size= 5802kB time=00:01:02.37 bitrate= 762.1kbits/s
  frame= 886 fps=160 q=2.0 size= 6363kB time=00:01:07.00 bitrate= 778.0kbits/s
  Buffer queue overflow, dropping.
  [Parsed_overlay_4 @ 0152ca80] Buffer queue overflow, dropping.
  Last message repeated 29 times
  frame= 954 fps=158 q=2.0 size= 6785kB time=00:01:13.31 bitrate= 758.2kbits/s
  frame= 1056 fps=162 q=2.0 size= 7377kB time=00:01:16.94 bitrate= 785.4kbits/s
  Buffer queue overflow, dropping.
  [Parsed_overlay_4 @ 0152ca80] Buffer queue overflow, dropping.
  Last message repeated 30 times
  frame= 1130 fps=161 q=2.0 size= 7789kB time=00:01:22.19 bitrate= 776.3kbits/s
  frame= 1217 fps=162 q=2.0 size= 8372kB time=00:01:27.68 bitrate= 782.1kbits/s
  frame= 1306 fps=163 q=2.0 size= 9074kB time=00:01:32.86 bitrate= 800.5kbits/s
  frame= 1393 fps=163 q=1.6 size= 9700kB time=00:01:38.41 bitrate= 807.3kbits/s
  frame= 1475 fps=163 q=2.0 size= 10278kB time=00:01:44.03 bitrate= 809.4kbits/s
  frame= 1568 fps=164 q=2.0 size= 10825kB time=00:01:48.52 bitrate= 817.1kbits/s
  frame= 1658 fps=165 q=2.0 size= 11439kB time=00:01:53.44 bitrate= 826.0kbits/s
  frame= 1734 fps=165 q=2.0 size= 12027kB time=00:01:58.31 bitrate= 832.7kbits/s
  frame= 1792 fps=162 q=2.0 size= 12579kB time=00:02:03.41 bitrate= 835.0kbits/s
  frame= 1851 fps=160 q=2.0 size= 13284kB time=00:02:10.74 bitrate= 832.3kbits/s
  frame= 1929 fps=160 q=2.0 size= 13922kB time=00:02:16.85 bitrate= 833.3kbits/s
  frame= 2010 fps=160 q=2.0 size= 14652kB time=00:02:23.39 bitrate= 837.1kbits/s
  frame= 2102 fps=161 q=2.0 size= 15329kB time=00:02:28.86 bitrate= 843.6kbits/s
  frame= 2200 fps=162 q=2.0 size= 15963kB time=00:02:34.08 bitrate= 848.7kbits/s
  frame= 2292 fps=163 q=2.0 size= 16554kB time=00:02:38.96 bitrate= 853.1kbits/s
  frame= 2378 fps=163 q=2.0 size= 17157kB time=00:02:44.50 bitrate= 854.4kbits/s
  frame= 2468 fps=164 q=2.0 size= 17826kB time=00:02:49.50 bitrate= 861.5kbits/s
  frame= 2564 fps=165 q=2.0 size= 18489kB time=00:02:54.43 bitrate= 868.3kbits/s
  Buffer queue overflow, dropping.
  [Parsed_overlay_4 @ 0152ca80] Buffer queue overflow, dropping.
  Last message repeated 15 times
  frame= 2647 fps=165 q=2.0 size= 19079kB time=00:02:59.53 bitrate= 870.6kbits/s
  frame= 2728 fps=165 q=2.0 Lsize= 19703kB time=00:03:04.13 bitrate= 876.6kbits/
  s video:19006kB audio:567kB subtitle:0 global headers:0kB muxing overhead 0.663315%

  Everything is working fine except that we want audio from both videos playing together in final overlayed file. I would be highly grateful if you can help in this and let me know if its possible to do via ffmpeg or not.