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• FFMPEG encode video with alpha channel to flv

  29 octobre 2013, par tree

  I'm trying to encode a video (mov) to an flv with alpha channel in FFMPEG but I can't seem to either

  1. find a codec that is supported
  2. find one that actually maintains the alpha

  Does anyone know how to set that up ?

  Thanks,

  ffmpeg -i abc_btr_1280x800_Takeover.mov -vcodec flv -pix_fmt yuv444p -s 1280x800 test4.flv

  here is the report...

  ffmpeg started on 2013-10-25 at 15:47:30
  
  Report written to "ffmpeg-20131025-154730.log"
  
  Command line: 
  
  ffmpeg -i abc_btr_1280x800_Takeover.mov -vcodec flv -pix_fmt yuv444p -s 1280x800     test4.flv -report
  
  ffmpeg version N-57367-g2f31b73 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Oct 23 2013 20:34:17 with gcc 4.8.2 (GCC)
  
    configuration: --disable-static --enable-shared --enable-gpl --enable-version3 --    disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --    enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-    libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --    enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  
    libavutil      52. 47.101 / 52. 47.101
  
    libavcodec     55. 38.101 / 55. 38.101
  
    libavformat    55. 19.104 / 55. 19.104
  
    libavdevice    55.  4.100 / 55.  4.100
  
    libavfilter     3. 89.100 /  3. 89.100
  
    libswscale      2.  5.101 /  2.  5.101
  
    libswresample   0. 17.104 /  0. 17.104
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Splitting the commandline.
  
  Reading option '-i' ... matched as input file with argument     'abc_btr_1280x800_Takeover.mov'.
  
  Reading option '-vcodec' ... matched as option 'vcodec' (force video codec ('copy' to     copy stream)) with argument 'flv'.
  
  Reading option '-pix_fmt' ... matched as option 'pix_fmt' (set pixel format) with argument 'yuv444p'.
  
  Reading option '-s' ... matched as option 's' (set frame size (WxH or abbreviation)) with argument '1280x800'.
  
  Reading option 'test4.flv' ... matched as output file.
  
  Reading option '-report' ... matched as option 'report' (generate a report) with argument '1'.
  
  Finished splitting the commandline.
  
  Parsing a group of options: global .
  
  Applying option report (generate a report) with argument 1.
  
  Successfully parsed a group of options.
  
  Parsing a group of options: input file abc_btr_1280x800_Takeover.mov.
  
  Successfully parsed a group of options.
  
  Opening an input file: abc_btr_1280x800_Takeover.mov.
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] Format mov,mp4,m4a,3gp,3g2,mj2 probed with size=2048 and score=100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] ISO: File Type Major Brand: qt  
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] File position before avformat_find_stream_info() is 281624339
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] All info found
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000000000085ac00] File position after avformat_find_stream_info() is 288732
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'abc_btr_1280x800_Takeover.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      creation_time   : 2013-09-22 02:50:18
  
    Duration: 00:00:10.00, start: 0.000000, bitrate: 225299 kb/s
  
      Stream #0:0(eng), 1, 1/24: Video: qtrle (rle  / 0x20656C72), bgra, 1280x800, 225293 kb/s, SAR 1280:1280 DAR 8:5, 24 fps, 24 tbr, 24 tbn, 24 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-09-22 02:50:18
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
      Stream #0:1(eng), 0, 1/24: Data: none (tmcd / 0x64636D74), 0 kb/s (default)
  
      Metadata:
  
        creation_time   : 2013-09-22 02:50:22
  
        handler_name    : Apple Alias Data Handler
  
        timecode        : 00:00:00:00
  
  Successfully opened the file.
  
  Parsing a group of options: output file test4.flv.
  
  Applying option vcodec (force video codec ('copy' to copy stream)) with argument flv.
  
  Applying option pix_fmt (set pixel format) with argument yuv444p.
  
  Applying option s (set frame size (WxH or abbreviation)) with argument 1280x800.
  
  Successfully parsed a group of options.
  
  Opening an output file: test4.flv.
  
  Successfully opened the file.
  
  detected 4 logical cores
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'video_size' to value '1280x800'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'pix_fmt' to value '30'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'time_base' to value '1/24'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'pixel_aspect' to value '1280/1280'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'sws_param' to value 'flags=2'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] Setting 'frame_rate' to value '24/1'
  
  [graph 0 input from stream 0:0 @ 0000000000303bc0] w:1280 h:800 pixfmt:bgra tb:1/24 fr:24/1 sar:1/1 sws_param:flags=2
  
  [scaler for output stream 0:0 @ 00000000003056a0] Setting 'w' to value '1280'
  
  [scaler for output stream 0:0 @ 00000000003056a0] Setting 'h' to value '800'
  
  [scaler for output stream 0:0 @ 00000000003056a0] Setting 'flags' to value '0x4'
  
  [scaler for output stream 0:0 @ 00000000003056a0] w:1280 h:800 flags:'0x4' interl:0
  
  Incompatible pixel format 'yuv444p' for codec 'flv', auto-selecting format 'yuv420p'
  
  [format @ 00000000002f8320] compat: called with args=[yuv420p]
  
  [format @ 00000000002f8320] Setting 'pix_fmts' to value 'yuv420p'
  
  [AVFilterGraph @ 000000000085bc60] query_formats: 5 queried, 4 merged, 0 already done, 0 delayed
  
  [scaler for output stream 0:0 @ 00000000003056a0] w:1280 h:800 fmt:bgra sar:1/1 -> w:1280 h:800 fmt:yuv420p sar:1/1 flags:0x4
  
  [flv @ 0000000000374be0] intra_quant_bias = 0 inter_quant_bias = -64
  
  Output #0, flv, to 'test4.flv':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      encoder         : Lavf55.19.104
  
      Stream #0:0(eng), 0, 1/1000: Video: flv1 (flv) ([2][0][0][0] / 0x0002), yuv420p,             1280x800 [SAR 1:1 DAR 8:5], q=2-31, 200 kb/s, 1k tbn, 24 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-09-22 02:50:18
  
            handler_name    : Apple Alias Data Handler
  
            timecode        : 00:00:00:00        
  
      Stream mapping:
  
        Stream #0:0 -> #0:0 (qtrle -> flv)
  
  Press [q] to stop, [?] for help
  
  frame=   27 fps=0.0 q=31.0 size=     351kB time=00:00:01.12 bitrate=2554.2kbits/s    
  
  frame=   46 fps= 45 q=31.0 size=     477kB time=00:00:01.91 bitrate=2039.5kbits/s    
  
  frame=   60 fps= 39 q=31.0 size=     543kB time=00:00:02.50 bitrate=1779.4kbits/s    
  
  frame=   74 fps= 36 q=31.0 size=     629kB time=00:00:03.08 bitrate=1672.4kbits/s    
  
  frame=   96 fps= 37 q=31.0 size=     795kB time=00:00:04.00 bitrate=1627.4kbits/s    
  
  frame=  123 fps= 40 q=31.0 size=     924kB time=00:00:05.12 bitrate=1477.0kbits/s    
  
  frame=  149 fps= 41 q=31.0 size=    1133kB time=00:00:06.20 bitrate=1494.7kbits/s    
  
  frame=  175 fps= 43 q=31.0 size=    1224kB time=00:00:07.29 bitrate=1375.5kbits/s    
  
  frame=  201 fps= 44 q=31.0 size=    1352kB time=00:00:08.37 bitrate=1322.7kbits/s    
  
  frame=  228 fps= 45 q=31.0 size=    1461kB time=00:00:09.50 bitrate=1260.1kbits/s    
  
  [output stream 0:0 @ 00000000003053c0] EOF on sink link output stream 0:0:default.
  
  No more output streams to write to, finishing.
  
  frame=  240 fps= 45 q=31.0 Lsize=    1600kB time=00:00:10.00 bitrate=1310.4kbits/s    
  
  
  
  video:1596kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.252476%
  
  240 frames successfully decoded, 0 decoding errors
  
  [AVIOContext @ 000000000032dfc0] Statistics: 3 seeks, 242 writeouts
  
  [AVIOContext @ 000000000085bde0] Statistics: 281664506 bytes read, 3 seeks

• FFmpeg : How to generate a .mp4 with h.265 Codec ?

  5 mai 2014, par skull3r7

  I want to encode a video file to H.265. The last version of ffmpeg should be support H.265 (Source).

  However, I could not find any information about the exact command.

  I do not know, which library I should indicate after -vcodec.

  EDIT : I use the lastest Zeranoe FFmpeg Build (git-c78a416 (2013-10-26)).

• How can I encode and segment audio files without having gaps (or audio pops) between segments when I reconstruct it ?

  16 mai 2013, par fenduru

  I'm working on a web application that requires streaming and synchronization of multiple audio files. For this, I am using the Web Audio API over HTML5 audio tags because of the importance of timing audio.

  Currently, I'm using FFMPEG's segmentation feature to encode and segment the audio files into smaller chunks. The reason I am segmenting them is so I can start streaming from the middle of the file instead of starting from the beginning (otherwise I would've just split the files using UNIX split, as shown here. The problem is that when I string the audio segments back together, I get an audio pop between segments.

  If I encode the segments using a PCM encoding (pcm_s24le) in a .wav file, the playback is seamless, which leads me to believe that the encoder is padding either the beginning or the end of the file. Since I will be dealing with many different audio files, using .wav would require far too much bandwidth.

  I'm looking to one of the following solutions to the problem :

  • How can I segment encoded audio files seamlessly,
  • How can I force an encoder to NOT pad audio frames using ffmpeg (or another utility), or
  • What is a better way to stream audio (starting at an arbitrary track time) without using an audio tag ?

  System Information

  • Custom node.js server
  • Upon upload of an audio file, node.js pipes the data into ffmpeg's encoder
  • Need to use HTML5 Web Audio API supported encoding
  • Server sends audio chunks 1 at a time through a WebSockets socket

  Thanks in advance. I've tried to be as clear as possible but if you need clarification I'd be more than willing to provide it.