[FFmpeg-user] Transcoding H264/1080p to H264/720p

[Mauricio Ulargui]

Hi,I'm transcoding a hi res H264/1080p video to H254/720p in order to be able to see it in low res devices (ie iPad2). The simple command I used (below) failed to provide a valid output and gets a warning. I also tried using -vsync 2 as suggested but didn't work either, the file produced doesn't play the video, only de audio. Checked this last output with ffprobe, looks like the video stream is there but it doesn't show with a player (tried several). Suggestions? ffmpeg version 1.1.1 Copyright (c) 2000-2013 the FFmpeg developers
  built on Jan 20 2013 23:05:28 with gcc 4.7.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  libavutil      52. 13.100 / 52. 13.100
  libavcodec     54. 86.100 / 54. 86.100
  libavformat    54. 59.106 / 54. 59.106
  libavdevice    54.  3.102 / 54.  3.102
  libavfilter     3. 32.100 /  3. 32.100
  libswscale      2.  1.103 /  2.  1.103
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  Metadata:
    major_brand     : 3gp4
    minor_version   : 512
    compatible_brands: 3gp4
  Duration: 00:00:43.44, start: 0.000000, bitrate: 12053 kb/s
    Stream #0:0(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s
    Metadata:
      handler_name    : SoundHandler
    Stream #0:1(eng): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, 11934 kb/s, 29.76 fps, 10k tbr, 10k tbn, 20k tbc
    Metadata:
      handler_name    : VideoHandler
[mp4 @ 03e28020] Frame rate very high for a muxer not efficiently supporting it.
Please consider specifying a lower framerate, a different muxer or -vsync 2
[libx264 @ 0248e8c0] MB rate (36000000) > level limit (2073600)
[libx264 @ 0248e8c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 AVX
[libx264 @ 0248e8c0] profile High, level 5.2
[libx264 @ 0248e8c0] 264 - core 129 r2245 bc13772 - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - 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=-2 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, mp4, to '.\to\video.mp4':
  Metadata:
    major_brand     : 3gp4
    minor_version   : 512
    compatible_brands: 3gp4
    encoder         : Lavf54.59.106
    Stream #0:0(eng): Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1280x720, q=-1--1, 10k tbn, 10k tbc
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:1 -> #0:0 (h264 -> libx264)
  Stream #0:0 -> #0:1 (aac -> aac)
Press [q] to stop, [?] for help
frame=  666 fps= 68 q=33.0 size=     526kB time=00:00:00.11 bitrate=37119.6kbits/s dup=665 drop=0    
frame= 1003 fps= 64 q=33.0 size=     778kB time=00:00:00.18 bitrate=34325.9kbits/s dup=1001 drop=0    
frame= 1682 fps= 79 q=33.0 size=    1462kB time=00:00:00.20 bitrate=57304.5kbits/s dup=1678 drop=0    
frame= 1682 fps= 62 q=33.0 size=    1462kB time=00:00:00.23 bitrate=51572.9kbits/s dup=1678 drop=0    
frame= 2016 fps= 62 q=33.0 size=    1706kB time=00:00:00.27 bitrate=50176.5kbits/s dup=2011 drop=0    
frame= 2850 fps= 71 q=33.0 size=    2377kB time=00:00:00.27 bitrate=69601.7kbits/s dup=2843 drop=0    
frame= 2850 fps= 60 q=33.0 size=    2584kB time=00:00:00.30 bitrate=70128.9kbits/s dup=2843 drop=0    
Received signal 2: terminating.

Mauricio  @ Ulargui .com | +1 425 449 3825