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• ffmpeg : "Input/output error" Read gif from named pipe ?

  23 octobre 2022, par Xirado

  I've been trying to debug this for hours now, and cannot seem to understand why it doesn't work.

  


  I want to overlay a png onto all frames of a gif, and since writing all the files to disk is slow, i wanted to use pipes.

  


  I created a named pipe using mkfifo imgstream1 and then launch ffmpeg :

  


  ffmpeg -report -hide_banner -v 9 -loglevel 99 -y -f gif -i imgstream1 out1.gif


  


  (This isn't actually useful as it just spits out the same gif again but it's simpler for debugging)

  


  After ffmpeg launches it waits for data from the pipe, so i write an actual gif file to the pipe using this kotlin code

  


  val backgroundFifo = File("imgstream1")
val inputOne = File("background.gif").readBytes()
println("background.gif -> ${inputOne.size} bytes")
val output = backgroundFifo.outputStream()
output.write(inputOne)
output.flush()
output.close()


  


  It prints : background.gif -> 7233247 bytes

  


  Now ffmpeg should read the bytes and spit out a gif, but it always seems to fail doing so.

  


  Opening an input file: imgstream1.
[gif @ 0x7714180] Opening 'imgstream1' for reading
[file @ 0x7714980] Setting default whitelist 'file,crypto,data'
[AVIOContext @ 0x7724dc0] Statistics: 7233247 bytes read, 0 seeks
imgstream1: Input/output error


  


  Sadly this does not give any further information, i'm already on the highest log level...

  


  I've tried multiple things :

  


  

  • -f image2pipe -> Works, but only loads the first 2 frames of the gif

  


  • Renaming the pipe to imgstream1.gif so ffmpeg thinks it's a gif file, no change.

  


  • Different ffmpeg versions

  


  • Using the actual gif as an ffmpeg input works

  


  


  At this point i have no idea what the problem might be, as ffmpeg seems to load all bytes.
It's worth noting that doing cat imgstream1 > file.gif produces the desired gif.

  


  Any help would be appreciated !

  


• ffmpeg Windows : standard transcode produces file that "uses unsupported encoding settings" [duplicate]

  17 août 2022, par David M. Cotter

  using the basic command :

  


  ffmpeg -i infile.mp4 -vcodec libx264 -acodec aac output.mp4


  


  poduces a file that can't be played by the standard Windows Media Player app.
Is there something i'm missing ?

  


  Here is the log data.

  


  C:> \\Mac\depot\kJams\External\ffmpeg\win\bin\ffmpeg.exe -i "\\Mac\Home\Desktop\Christina lying down.AVI" -vcodec libx264 -acodec aac output.mp4
ffmpeg version git-2019-11-01-53c21c2 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9.2.1 (GCC) 20191010
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  libavutil      56. 35.101 / 56. 35.101
  libavcodec     58. 60.100 / 58. 60.100
  libavformat    58. 33.100 / 58. 33.100
  libavdevice    58.  9.100 / 58.  9.100
  libavfilter     7. 66.100 /  7. 66.100
  libswscale      5.  6.100 /  5.  6.100
  libswresample   3.  6.100 /  3.  6.100
  libpostproc    55.  6.100 / 55.  6.100
Guessed Channel Layout for Input Stream #0.1 : mono
Input #0, avi, from '\\Mac\Home\Desktop\Christina lying down.AVI':
  Metadata:
    creation_time   : 2006-01-26 18:19:22
    encoder         : CanonMVI02
  Duration: 00:00:07.70, start: 0.000000, bitrate: 14928 kb/s
    Stream #0:0: Video: mjpeg (Baseline) (MJPG / 0x47504A4D), yuvj422p(pc, bt470bg/unknown/unknown), 640x480, 14896 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc
    Stream #0:1: Audio: pcm_u8 ([1][0][0][0] / 0x0001), 11024 Hz, mono, u8, 88 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (pcm_u8 (native) -> aac (native))
Press [q] to stop, [?] for help
[aac @ 0f06a740] Too many bits 6408.707483 > 6144 per frame requested, clamping to max
[libx264 @ 0f068b40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2
[libx264 @ 0f068b40] profile High 4:2:2, level 3.0, 4:2:2, 8-bit
[libx264 @ 0f068b40] 264 - core 158 - H.264/MPEG-4 AVC codec - Copyleft 2003-2019 - 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=12 lookahead_threads=2 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 'output.mp4':
  Metadata:
    encoder         : Lavf58.33.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuvj422p(pc), 640x480, q=-1--1, 30 fps, 1000k tbn, 30 tbc
    Metadata:
      encoder         : Lavc58.60.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
    Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 11025 Hz, mono, fltp, 66 kb/s
    Metadata:
      encoder         : Lavc58.60.100 aac
frame=  231 fps=128 q=-1.0 Lsize=    1570kB time=00:00:07.70 bitrate=1668.3kbits/s speed=4.28x
video:1514kB audio:51kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.347234%
[libx264 @ 0f068b40] frame I:2     Avg QP:24.57  size: 27076
[libx264 @ 0f068b40] frame P:60    Avg QP:26.24  size: 12693
[libx264 @ 0f068b40] frame B:169   Avg QP:27.91  size:  4342
[libx264 @ 0f068b40] consecutive B-frames:  1.7%  1.7%  1.3% 95.2%
[libx264 @ 0f068b40] mb I  I16..4:  0.6% 97.6%  1.8%
[libx264 @ 0f068b40] mb P  I16..4:  0.1% 10.6%  0.5%  P16..4: 51.1% 17.9% 10.8%  0.0%  0.0%    skip: 8.9%
[libx264 @ 0f068b40] mb B  I16..4:  0.0%  1.2%  0.0%  B16..8: 51.8%  4.4%  0.7%  direct: 6.4%  skip:35.5%  L0:48.8% L1:46.4% BI: 4.8%
[libx264 @ 0f068b40] 8x8 transform intra:95.6% inter:78.5%
[libx264 @ 0f068b40] coded y,uvDC,uvAC intra: 89.0% 85.1% 53.7% inter: 29.0% 44.7% 6.7%
[libx264 @ 0f068b40] i16 v,h,dc,p: 19% 31%  8% 42%
[libx264 @ 0f068b40] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 11% 15% 33%  6%  7%  5%  9%  5%  8%
[libx264 @ 0f068b40] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 14% 21% 18%  7% 10%  6% 11%  5%  6%
[libx264 @ 0f068b40] i8c dc,h,v,p: 67% 13% 15%  5%
[libx264 @ 0f068b40] Weighted P-Frames: Y:8.3% UV:6.7%
[libx264 @ 0f068b40] ref P L0: 35.8% 10.5% 35.1% 17.4%  1.2%
[libx264 @ 0f068b40] ref B L0: 76.1% 19.2%  4.7%
[libx264 @ 0f068b40] ref B L1: 92.7%  7.3%
[libx264 @ 0f068b40] kb/s:1609.92
[aac @ 0f06a740] Qavg: 34311.295


  


  Ignore this part, Stack Overflow now requires that i type something more so it's not "mostly code"

  


• FFmpeg re-wrap of a TS-AAC audio transport stream file to M4A-AAC : what happens by default (no "-codec copy" etc.) ?

  22 avril 2022, par esp

  What happens if you simply do ffmpeg -i aFile.ts aFile.m4a as opposed to ffmpeg -i aFile.ts -codec copy aFile.m4a, when the TS file contains only a single stream, namely AAC, and knowing that m4a files also typically contain AAC.

  


  Does ffmpeg - even in the absence of any filters etc. - decode the original AAC and re-encode back to AAC (with whatever default parameters ffmpeg assumes for that - not necessarily matching those of the original) ? Or does it do something else ?

  


  I tried this both with and without "-codec copy" and the results in each case were AAC but the files were significantly different in size (Original TS : 8.5 MB, ffmpeg'd without "-codec copy" 7 MB, ffmpeg'd with latter 5.1 MB.

  


  At https://ffmpeg.org/ffmpeg.html it is stated (under "3.2 Stream copy"...

  


  


  Stream copy is a mode selected by supplying the copy parameter to the
-codec option. It makes ffmpeg omit the decoding and encoding step for the specified stream, so it does only demuxing and muxing. It is
useful for changing the container format or modifying container-level
metadata.
Implied by the inverse of that situation is that, in the absence of "-codec copy", ffmpeg will carry out the decoding and encoding steps.