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• Converting AAC stream to DASH MP4 with high fragment length precision

  5 mars 2017, par vdudouyt

  For my HTML5 project I need to create a fragmented MP4 file with a single audio stream (no video), each fragment of which has a duration of exactly 0.1 second.

  Accordingly to ffmpeg docs, you can accomplish that by passing a value in microseconds with ’-frag_duration’ - which I found to be working and playable with HTML5 MediaSource API :

  $ ffmpeg -y -i input.aac -c:a libfdk_aac -b:a 64k -level:v 13 -r 25 -strict experimental -movflags empty_moov+default_base_moof -frag_duration 100000 output.mp4

  As we have a 210 second audio split up by 0.1s fragments, I expect that in output.mp4 we’d have 2100 fragments, hence 2100 moof atoms. But, upon inspecting it I’ve figured out that we only have 1811 moof atoms - which means that some (or maybe even all) fragments are bigger than expected :

  $ python ~/git/mp4viewer/src/showboxes.py output.mp4 |grep moof|wc -l
  
  1811

  Could anybody tell me what’s wrong, and how could I accomplish what I want ?

  Right now my assumption is that during an encoding I have AAC frame length which is not a multiple of 0.1s, hence ffmpeg has no chance to produce the fragments that are strictly equal to 0.1s but I’m not sure. If somebody can confirm that - and let me know a way to explicitly set AAC frame_size in FFMPEG (I couldn’t find anything like that in the docs), or completely disprove this - it would be also highly appreciated.

• Silence "string-plus-int" warning shown by clang.

  6 janvier 2020, par Carl Eugen Hoyos

  Silence "string-plus-int" warning shown by clang.
  libswscale/utils.c:89:42 : warning : adding 'unsigned long' to a string does not append to the string [-Wstring-plus-int]
  

  • [DH] libavcodec/utils.c
  • [DH] libavdevice/avdevice.c
  • [DH] libavfilter/avfilter.c
  • [DH] libavformat/utils.c
  • [DH] libavutil/utils.c
  • [DH] libpostproc/postprocess.c
  • [DH] libswresample/swresample.c
  • [DH] libswscale/utils.c

• FFmpeg encode 8192x8192@60 with high quality from image sequence

  20 décembre 2017, par Daniel R.

  I am looking for the right ffmpeg config or an alternative software to encode a long sequence of images captured with 60fps and a resolution of 8192x8192 pixel.

  What i tried is to use h264 encoding, but at this high resolution it cannot be suitable since i couldnt play the encoded video.

  Using h265/HEVC i can play the video but i have nasty compression artifacts especially at the borders of the image.

  Here is the command i used with ffmpeg-3.4.1 at Windows 64-bit static Lib :

  .\ffmpeg.exe -framerate 60 -i ""E:\RenderedFrames\img%d.jpg"" -c:v libx265 -crf 28 output.mp4

  Here is the log of ffmpeg

  C:\ffmpeg-20171218-74f408c-win64-static\bin> .\ffmpeg.exe -framerate 60 -i ""D:\SansSousi\%d.jpg"" -c:v 
  
  libx265 -crf 27 output3.mp4 
  
  ffmpeg version git-2017-12-18-74f408c Copyright (c) 2000-2017 the FFmpeg developers 
  
  built with gcc 7.2.0 (GCC) 
  
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --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-amf --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx 
  
  libavutil 56. 6.100 / 56. 6.100 
  
  libavcodec 58. 8.100 / 58. 8.100 
  
  libavformat 58. 3.100 / 58. 3.100 
  
  libavdevice 58. 0.100 / 58. 0.100 
  
  libavfilter 7. 7.100 / 7. 7.100 
  
  libswscale 5. 0.101 / 5. 0.101 
  
  libswresample 3. 0.101 / 3. 0.101 
  
  libpostproc 55. 0.100 / 55. 0.100 
  
  Input #0, image2, from 'D:\SansSousi\%d.jpg': 
  
  Duration: 00:00:03.02, start: 0.000000, bitrate: N/A 
  
  Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 8192x8192 [SAR 1:1 DAR 1:1], 60 tbr, 60 tbn, 60 tbc 
  
  Stream mapping: 
  
  Stream #0:0 -> #0:0 (mjpeg (native) -> hevc (libx265)) 
  
  Press [q] to stop, [?] for help 
  
  [swscaler @ 0000027b64c702c0] deprecated pixel format used, make sure you did set range correctly 
  
  x265 [info]: HEVC encoder version 2.6×6b079854e56e 
  
  x265 [info]: build info [Windows][GCC 7.2.0][64 bit] 8bit 
  
  x265 [info]: using cpu capabilities: MMX2 SSE2Fast LZCNT SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 
  
  x265 [info]: Main profile, Level-8.5 (Main tier) 
  
  x265 [info]: Thread pool created using 16 threads 
  
  x265 [info]: Slices : 1 
  
  x265 [info]: frame threads / pool features : 4 / wpp(128 rows) 
  
  x265 [info]: Coding QT: max CU size, min CU size : 64 / 8 
  
  x265 [info]: Residual QT: max TU size, max depth : 32 / 1 inter / 1 intra 
  
  x265 [info]: ME / range / subpel / merge : hex / 57 / 2 / 2 
  
  x265 [info]: Keyframe min / max / scenecut / bias: 25 / 250 / 40 / 5.00 
  
  x265 [info]: Lookahead / bframes / badapt : 20 / 4 / 2 
  
  x265 [info]: b-pyramid / weightp / weightb : 1 / 1 / 0 
  
  x265 [info]: References / ref-limit cu / depth : 3 / on / on 
  
  x265 [info]: AQ: mode / str / qg-size / cu-tree : 1 / 1.0 / 32 / 1 
  
  x265 [info]: Rate Control / qCompress : CRF-27.0 / 0.60 
  
  x265 [info]: tools: rd=3 psy-rd=2.00 rskip signhide tmvp strong-intra-smoothing 
  
  x265 [info]: tools: lslices=8 deblock sao 
  
  Output #0, mp4, to 'output3.mp4': 
  
  Metadata: 
  
  encoder : Lavf58.3.100 
  
  Stream #0:0: Video: hevc (libx265) (hev1 / 0x31766568), yuv420p, 8192x8192 [SAR 1:1 DAR 1:1], q=2-31, 60 fps, 15360 tbn, 60 tbc 
  
  Metadata: 
  
  encoder : Lavc58.8.100 libx265 
  
  frame= 33 fps=1.8 q=-0.0 size= 1024kB time=00:00:00.00 bitrate=129060923.1kbits/s speed=3.63e-006x frame= 181 fps=1.1 q=-0.0 Lsize= 8112kB time=00:00:02.96 bitrate=22398.3kbits/s speed=0.0183x 
  
  video:8107kB audio:0kB subtitle:0kB other streams:0kB global headers:2kB muxing overhead: 0.060955% 
  
  x265 [info]: frame I: 1, Avg QP:28.18 kb/s: 528757.92 
  
  x265 [info]: frame P: 36, Avg QP:30.76 kb/s: 36726.89 
  
  x265 [info]: frame B: 144, Avg QP:35.78 kb/s: 14814.45 
  
  x265 [info]: Weighted P-Frames: Y:0.0% UV:0.0% 
  
  x265 [info]: consecutive B-frames: 2.7% 0.0% 0.0% 0.0% 97.3% 
  
  
  
  encoded 181 frames in 161.36s (1.12 fps), 22012.19 kb/s, Avg QP:34.74

  What can i do to improve the quality of the encoded video ?
  File size is secondary