Recherche avancée

Sur d’autres sites (9536)

• FFmpeg audio formats : ipod vs mov (for ALAC)

  22 juillet 2022, par Fabien Snauwaert

  In converting to Apple Lossless (ALAC) using FFmpeg, I have two options :

  


  ffmpeg -y -i whatever.wav -b:a 256k -ar 16000 -ac 1 -f ipod -acodec:a alac whatever.ipod.m4a
# Output #0, ipod, to 'content/tests/comparing-codecs/whatever.ipod.m4a':

ffmpeg -y -i whatever.wav -b:a 256k -ar 16000 -ac 1 -f mov -acodec:a alac whatever.mov.m4a
# Output #0, mov, to 'content/tests/comparing-codecs/whatever.mov.m4a':


  


  (I could also leave the -f alone, which the defaults to ipod.)

  


  This results in near identical files, from ffprobe :

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'content/tests/comparing-codecs/whatever.ipod.m4a':
  Metadata:
    major_brand     : M4A
    minor_version   : 512
    compatible_brands: isomiso2
    encoder         : Lavf58.29.100
  Duration: 00:00:01.46, start: 0.000000, bitrate: 67 kb/s
    Stream #0:0(und): Audio: alac (alac / 0x63616C61), 16000 Hz, mono, s16p, 63 kb/s (default)
    Metadata:
      handler_name    : SoundHandler


  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'content/tests/comparing-codecs/whatever.mov.m4a':
  Metadata:
    major_brand     : qt
    minor_version   : 512
    compatible_brands: qt
    encoder         : Lavf58.29.100
  Duration: 00:00:01.46, start: 0.000000, bitrate: 67 kb/s
    Stream #0:0: Audio: alac (alac / 0x63616C61), 16000 Hz, mono, s16p, 63 kb/s (default)
    Metadata:
      handler_name    : SoundHandler


  


  Only the file size is slightly different, with the ipod file 43 bytes smaller.

  


  I'm able to play both files in on macOS and iPhone, at least on the devices I had access to.

  


  My question is : is there any practical difference between formats ? Is a given format preferable for a specific use ?

  


• correctly escaping text in drawtext filter

  6 novembre 2013, par mente

  According to documentation %{}:, should be escaped with slash. But when I escape % the text is not added. There's error message saying Stray % near ')'. But what does it mean and how I can fix it ? Command and output :

  $ /usr/bin/ffmpeg -y -i /home/www/255871.mov -af 'aresample=async=1:min_hard_comp=0.100000' -vf 'scale=480:trunc(ow/a/2)*2,transpose=1 [in];movie=watermarks/text-box440.mov,scale=320:55 [bg];[in][bg] overlay=x=20:y=main_h-80,drawtext=fontsize=20:fix_bounds=1:fontfile=Helvetica\\:Style=bold:fontcolor=0xe6b300:text=small kitten \%\):x=30:y=h-80+ascent/2:draw=gte(t\,0)\;lt(t\,5) [out]' -pix_fmt yuv420p -r 24.39 -map_metadata -1 -movflags +faststart -f mp4 -vcodec libx264 -b:v 800k -maxrate 1100k -bufsize 2M -bt 256k -profile:vbaseline -acodec libfdk_aac -ab 64k -ar 44100 -ac 1 /tmp/kitten.mp4
  
  ffmpeg version 1.2 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Mar 15 2013 18:40:14 with gcc 4.4.6 (GCC) 20120305 (Red Hat 4.4.6-4)
  
    configuration: --enable-gpl --enable-libmp3lame --enable-libvo-aacenc --enable-libx264 --enable-version3 --enable-pthreads --enable-libfaac --enable-nonfree --enable-libfdk_a
  
  ac --enable-fontconfig --enable-libfreetype
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  2.100 / 52.  2.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/www/255871.mov':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 0
  
      compatible_brands: qt
  
      creation_time   : 2012-07-17 07:42:35
  
      model           : iPhone 3GS
  
      model-rus       : iPhone 3GS
  
      encoder         : 4.2.1
  
      encoder-rus     : 4.2.1
  
      date            : 2012-07-17T10:42:35+0300
  
      date-rus        : 2012-07-17T10:42:35+0300
  
      make            : Apple
  
      make-rus        : Apple
  
    Duration: 00:00:09.38, start: 0.000000, bitrate: 790 kb/s
  
      Stream #0:0(und): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p, 480x360, 720 kb/s, 29.97 fps, 29.97 tbr, 600 tbn, 1200 tbc
  
      Metadata:
  
        rotate          : 90
  
        creation_time   : 2012-07-17 07:42:35
  
        handler_name    : Core Media Data Handler
  
      Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 63 kb/s
  
      Metadata:
  
        creation_time   : 2012-07-17 07:42:35
  
        handler_name    : Core Media Data Handler
  
  [Parsed_drawtext_5 @ 0x2ae9b00] Using "/usr/share/fonts/default/Type1/n019003l.pfb"
  
  [libx264 @ 0x2ae7d40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
  [libx264 @ 0x2ae7d40] profile Constrained Baseline, level 2.1
  
  [libx264 @ 0x2ae7d40] 264 - core 130 r2274 c832fe9 - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html - options: cabac=0 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=0 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=0 weightp=0 keyint=250 keyint_min=24 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=abr mbtree=1 bitrate=800 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_maxrate=1100 vbv_bufsize=2000 nal_hrd=none ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to '/tmp/kitten.mp4':
  
    Metadata:
  
      encoder         : Lavf54.63.104
  
      Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 360x480, q=-1--1, 800 kb/s, 19512 tbn, 24.39 tbc
  
      Stream #0:1: Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, mono, s16, 64 kb/s
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 -> libx264)
  
    Stream #0:1 -> #0:1 (aac -> libfdk_aac)
  
  Press [q] to stop, [?] for help
  
  [Parsed_drawtext_5 @ 0x2ae9b00] Stray % near ')'
  
      Last message repeated 201 times
  
  Stray % near ')'0.0 q=27.0 size=     480kB time=00:00:07.96 bitrate= 493.4kbits/s dup=0 drop=35
  
  [Parsed_drawtext_5 @ 0x2ae9b00] Stray % near ')'
  
      Last message repeated 77 times
  
  Starting second pass: moving header on top of the file
  
  frame=  231 fps=0.0 q=-1.0 Lsize=    1002kB time=00:00:09.47 bitrate= 866.6kbits/s dup=0 drop=50
  
  video:921kB audio:74kB subtitle:0 global headers:0kB muxing overhead 0.680957%
  
  [libx264 @ 0x2ae7d40] frame I:1     Avg QP:24.43  size: 13264
  
  [libx264 @ 0x2ae7d40] frame P:230   Avg QP:23.72  size:  4041
  
  [libx264 @ 0x2ae7d40] mb I  I16..4: 24.8%  0.0% 75.2%
  
  [libx264 @ 0x2ae7d40] mb P  I16..4:  2.3%  0.0%  4.8%  P16..4: 34.4% 28.8%  9.4%  0.0%  0.0%    skip:20.3%
  
  [libx264 @ 0x2ae7d40] coded y,uvDC,uvAC intra: 62.5% 54.2% 4.4% inter: 19.6% 20.3% 0.1%
  
  [libx264 @ 0x2ae7d40] i16 v,h,dc,p: 36% 29% 19% 16%
  
  [libx264 @ 0x2ae7d40] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 21% 20%  6%  8%  7%  7%  6%  6%
  
  [libx264 @ 0x2ae7d40] i8c dc,h,v,p: 65% 15% 17%  3%
  
  [libx264 @ 0x2ae7d40] ref P L0: 93.4%  4.3%  2.3%
  
  [libx264 @ 0x2ae7d40] kb/s:796.32

• Codec not found while H.264 encoding using FFMPEG in iOS

  12 juin 2013, par Sukhpal Singh

  I am trying to encode video in h.264 format using FFMpeg in iOS. Actually I am receiving sample buffer from iPhone Camera and then converting it AVFrame and further from AVFrame to H.264 video. But while h.264 encoding if I use :

  codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);

  Then codec is found but if I use :

  codec = avcodec_find_encoder(CODEC_ID_H264);

  Then codec is nil means codec not found. Full code is as below :

  static void encode(AVFrame *picture)
  
   {
  
       AVCodec *codec;
  
       AVCodecContext *c= NULL;
  
       int i, out_size, size,  outbuf_size;
  
       uint8_t *outbuf, *picture_buf;
  
  
  
       printf("Video encoding\n");
  
  
  
       /* find the mpeg1 video encoder */
  
  
  
       //avcodec_init() ; // Also tried this but giving warning and not worked
  
       avcodec_register_all();
  
  
  
       codec = avcodec_find_encoder(CODEC_ID_H264);
  
       if (!codec) {
  
           fprintf(stderr, "codec not found\n");
  
           exit(1);
  
       }
  
  
  
       c= avcodec_alloc_context();
  
       picture= avcodec_alloc_frame();
  
  
  
       /* put sample parameters */
  
       c->bit_rate = 400000;
  
       /* resolution must be a multiple of two */
  
       c->width  = 352;
  
       c->height = 288;
  
       /* frames per second */
  
       c->time_base= (AVRational){1,25};
  
       c->gop_size = 10; /* emit one intra frame every ten frames */
  
       c->max_b_frames=1;
  
       c->pix_fmt = PIX_FMT_YUV420P;
  
  
  
       /* open it */
  
       if (avcodec_open(c, codec) < 0) {
  
           fprintf(stderr, "could not open codec\n");
  
           exit(1);
  
       }
  
  
  
           /* alloc image and output buffer */
  
       outbuf_size = 100000;
  
       outbuf = malloc(outbuf_size);
  
       size = c->width * c->height;
  
       picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
  
  
  
       out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
  
  
  
       NSLog(@"NSdada===%@",[NSData dataWithBytes:(const void *)outbuf length:out_size]);
  
  
  
       free(picture_buf);
  
       free(outbuf);
  
  
  
       avcodec_close(c);
  
       av_free(c);
  
       av_free(picture);
  
       printf("\n");
  
   }