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• ffmpeg - splitting, overlaying and selecting frame range in multiple input/outputs with complex video filter producing empty output

  11 octobre 2017, par Josep Carner

  I am trying to use ffmpeg to apply multiple filters -single input, multiple outputs-. In concrete, I am splitting the output in two, then applying an overlaying patch to one of those streams, split again and select a time range. The command I am using is :

     ffmpeg \
  
      -i ./dataset_test/videos/jz_10_huron_barstow.mkv \
  
      -an \
  
      -sn \
  
      -loglevel error \
  
      -filter_complex \
  
          "[0:v]split=2[L_in][F_in];
  
           [L_in]
  
              crop=226:307:21:74,scale=200x200,setdar=200:200,split=2\
  
           [L_in_0][L_in_1];\
  
           color=#808080:226x307,setpts=PTS-STARTPTS[L_PATCH];\
  
           [F_in][L_PATCH]
  
              overlay=21:74:shortest=1,scale=200x200,setdar=200:200,split=2\
  
           [F_in_0][F_in_1];\
  
           [F_in_0]select='between(t\,32\,212)',select='not(mod(n\,20))',setpts=(PTS-STARTPTS)/20[F_0];\
  
           [F_in_1]select='between(t\,213\,393)',select='not(mod(n\,20))',setpts=(PTS-STARTPTS)/20[F_1];\
  
           [L_in_0]select='between(t\,32\,212)',select='not(mod(n\,20))',setpts=(PTS-STARTPTS)/20[L_0];\
  
           [L_in_1]select='between(t\,213\,393)',select='not(mod(n\,20))',setpts=(PTS-STARTPTS)/20[L_1]\
  
           "\
  
      -map [F_0] -an -sn ./out/jz_10_huron_barstow/F/0_F.mp4\
  
      -map [F_1] -an -sn ./out/jz_10_huron_barstow/F/1_F.mp4\
  
      -map [L_0] -an -sn ./out/jz_10_huron_barstow/L/0_L.mp4\
  
      -map [L_1] -an -sn ./out/jz_10_huron_barstow/L/1_L.mp4\

  For some reason, 0_F.mp4 is empty and 1_F.mp4 is cropped. My intuition is that it has something to do with applying splitting + overlaying + selecting. I think at some point some filter before select is changing the PTS of the frames in some way select is not properly discarding them, but I honestly don’t know how to solve it. Some insights :

  1. L_0 and L_1 are fine (no overlay is used in those two)

  2. If I suppress L outputs everything works fine (no "split" is needed at the beginning)

  Could someone provide some light ? I don’t really know what else to try.
  The logs with loglevel 40 are (some repeated lines ommited) :

  ffmpeg version 2.8.1 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with Apple LLVM version 9.0.0 (clang-900.0.37)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.8.1_1 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-opencl --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-vda
  
    libavutil      54. 31.100 / 54. 31.100
  
    libavcodec     56. 60.100 / 56. 60.100
  
    libavformat    56. 40.101 / 56. 40.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 40.101 /  5. 40.101
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.101 /  1.  2.101
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, matroska,webm, from './dataset_test/videos/jz_10_huron_barstow.mkv':
  
    Metadata:
  
      ENCODER         : Lavf57.66.104
  
    Duration: 00:24:04.14, start: 0.000000, bitrate: 2117 kb/s
  
      Stream #0:0: Video: h264 (Main), 1 reference frame, yuv420p, 1440x900 (1440x912) [SAR 1:1 DAR 8:5], 30 fps, 30 tbr, 1k tbn, 60 tbc (default)
  
      Metadata:
  
        ENCODER         : Lavc57.83.100 h264_nvenc
  
        DURATION        : 00:24:04.102000000
  
      Stream #0:1: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s (default)
  
      Metadata:
  
        ENCODER         : Lavc57.83.100 ac3
  
        DURATION        : 00:24:04.135000000
  
  [Parsed_scale_2 @ 0x7fdfd2403d20] w:200 h:200 flags:'bilinear' interl:0
  
  [Parsed_setdar_3 @ 0x7fdfd240ad80] num:den syntax is deprecated, please use num/den or named options instead
  
  [Parsed_color_5 @ 0x7fdfd24096a0] size:226x307 rate:25/1 duration:-1.000000 sar:1/1
  
  [Parsed_scale_8 @ 0x7fdfd24092c0] w:200 h:200 flags:'bilinear' interl:0
  
  [Parsed_setdar_9 @ 0x7fdfd240b360] num:den syntax is deprecated, please use num/den or named options instead
  
  [Parsed_scale_2 @ 0x7fdfd2509b00] w:200 h:200 flags:'bilinear' interl:0
  
  [Parsed_setdar_3 @ 0x7fdfd25092c0] num:den syntax is deprecated, please use num/den or named options instead
  
  [Parsed_color_5 @ 0x7fdfd250a520] size:226x307 rate:25/1 duration:-1.000000 sar:1/1
  
  [Parsed_scale_8 @ 0x7fdfd250b620] w:200 h:200 flags:'bilinear' interl:0
  
  [Parsed_setdar_9 @ 0x7fdfd250a960] num:den syntax is deprecated, please use num/den or named options instead
  
  [graph 0 input from stream 0:0 @ 0x7fdfd2511360] w:1440 h:900 pixfmt:yuv420p tb:1/1000 fr:30/1 sar:1/1 sws_param:flags=2
  
  [Parsed_crop_1 @ 0x7fdfd2509c80] w:1440 h:900 sar:1/1 -> w:226 h:306 sar:1/1
  
  [Parsed_scale_2 @ 0x7fdfd2509b00] w:226 h:306 fmt:yuv420p sar:1/1 -> w:200 h:200 fmt:yuv420p sar:113/153 flags:0x2
  
  [Parsed_setdar_3 @ 0x7fdfd25092c0] w:200 h:200 dar:113/153 sar:113/153 -> dar:1/1 sar:1/1
  
  [Parsed_select_21 @ 0x7fdfd250a760] TB:0.001000 FRAME_RATE:30.000000 SAMPLE_RATE:nan
  
  [Parsed_select_18 @ 0x7fdfd250a080] TB:0.001000 FRAME_RATE:30.000000 SAMPLE_RATE:nan
  
  [Parsed_color_5 @ 0x7fdfd250a520] TB:0.040000 FRAME_RATE:25.000000 SAMPLE_RATE:nan
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] main w:1440 h:900 fmt:yuv420p overlay w:226 h:306 fmt:yuva420p eof_action:endall
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Selected 1/1000 time base
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Sync level 2
  
  [Parsed_scale_8 @ 0x7fdfd250b620] w:1440 h:900 fmt:yuv420p sar:1/1 -> w:200 h:200 fmt:yuv420p sar:8/5 flags:0x2
  
  [Parsed_setdar_9 @ 0x7fdfd250a960] w:200 h:200 dar:8/5 sar:8/5 -> dar:1/1 sar:1/1
  
  [Parsed_select_15 @ 0x7fdfd250dd00] TB:0.001000 FRAME_RATE:30.000000 SAMPLE_RATE:nan
  
  [Parsed_select_12 @ 0x7fdfd250ca60] TB:0.001000 FRAME_RATE:30.000000 SAMPLE_RATE:nan
  
  [libx264 @ 0x7fdfd4005e00] using SAR=1/1
  
  [libx264 @ 0x7fdfd4005e00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 0x7fdfd4005e00] profile High, level 1.2
  
  [libx264 @ 0x7fdfd4005e00] 264 - core 148 r2601 a0cd7d3 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - 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
  
  [libx264 @ 0x7fdfd400f600] using SAR=1/1
  
  [libx264 @ 0x7fdfd400f600] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 0x7fdfd400f600] profile High, level 1.2
  
  [libx264 @ 0x7fdfd400f600] 264 - core 148 r2601 a0cd7d3 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - 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
  
  [libx264 @ 0x7fdfd4018e00] using SAR=1/1
  
  [libx264 @ 0x7fdfd4018e00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 0x7fdfd4018e00] profile High, level 1.2
  
  [libx264 @ 0x7fdfd4018e00] 264 - core 148 r2601 a0cd7d3 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - 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
  
  [libx264 @ 0x7fdfd4022600] using SAR=1/1
  
  [libx264 @ 0x7fdfd4022600] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 0x7fdfd4022600] profile High, level 1.2
  
  [libx264 @ 0x7fdfd4022600] 264 - core 148 r2601 a0cd7d3 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - 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 './out/jz_10_huron_barstow/F/0_F.mp4':
  
    Metadata:
  
      encoder         : Lavf56.40.101
  
      Stream #0:0: Video: h264 (libx264), -1 reference frame ([33][0][0][0] / 0x0021), yuv420p, 200x200 [SAR 1:1 DAR 1:1], q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
  
      Metadata:
  
        encoder         : Lavc56.60.100 libx264
  
  Output #1, mp4, to './out/jz_10_huron_barstow/F/1_F.mp4':
  
    Metadata:
  
      encoder         : Lavf56.40.101
  
      Stream #1:0: Video: h264 (libx264), -1 reference frame ([33][0][0][0] / 0x0021), yuv420p, 200x200 [SAR 1:1 DAR 1:1], q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
  
      Metadata:
  
        encoder         : Lavc56.60.100 libx264
  
  Output #2, mp4, to './out/jz_10_huron_barstow/L/0_L.mp4':
  
    Metadata:
  
      encoder         : Lavf56.40.101
  
      Stream #2:0: Video: h264 (libx264), -1 reference frame ([33][0][0][0] / 0x0021), yuv420p, 200x200 [SAR 1:1 DAR 1:1], q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
  
      Metadata:
  
        encoder         : Lavc56.60.100 libx264
  
  Output #3, mp4, to './out/jz_10_huron_barstow/L/1_L.mp4':
  
    Metadata:
  
      encoder         : Lavf56.40.101
  
      Stream #3:0: Video: h264 (libx264), -1 reference frame ([33][0][0][0] / 0x0021), yuv420p, 200x200 [SAR 1:1 DAR 1:1], q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
  
      Metadata:
  
        encoder         : Lavc56.60.100 libx264
  
  Stream mapping:
  
    Stream #0:0 (h264) -> split
  
    setpts -> Stream #0:0 (libx264)
  
    setpts -> Stream #1:0 (libx264)
  
    setpts -> Stream #2:0 (libx264)
  
    setpts -> Stream #3:0 (libx264)
  
  Press [q] to stop, [?] for help
  
  [swscaler @ 0x7fdfd3800000] Warning: data is not aligned! This can lead to a speedloss
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 210 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 262 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 239 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 195 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 211 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 255 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 148 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 174 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 182 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 193 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:00.26 bitrate=   1.4kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 156 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:00.53 bitrate=   0.7kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 154 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:00.76 bitrate=   0.5kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 155 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:01.03 bitrate=   0.4kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 231 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:01.43 bitrate=   0.3kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 260 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:01.86 bitrate=   0.2kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 256 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:02.30 bitrate=   0.2kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 209 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:02.63 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 253 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:03.06 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 160 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:03.33 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 189 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:03.63 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 201 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:03.96 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 251 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:04.40 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 246 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:04.80 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 257 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:05.23 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 258 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:05.66 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 251 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:06.10 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 274 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:06.56 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 282 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:07.03 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Buffer queue overflow, dropping.
  
      Last message repeated 185 times
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=0.0 q=29.0 q=0.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=29.0 q=29.0 q=29.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=29.0 q=29.0 q=29.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=29.0 q=29.0 q=29.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=29.0 q=29.0 q=29.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  frame=    0 fps=0.0 q=0.0 q=29.0 q=29.0 q=29.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  […]   
  
  frame=    0 fps=0.0 q=0.0 q=29.0 q=29.0 q=29.0 size=       0kB time=00:00:07.26 bitrate=   0.1kbits/s    
  
  [Parsed_overlay_7 @ 0x7fdfd250b020] [framesync @ 0x7fdfd250b708] Sync level 1
  
  No more output streams to write to, finishing.
  
  frame=    0 fps=0.0 q=0.0 Lq=-1.0 q=-1.0 q=-1.0 size=       0kB time=00:00:08.93 bitrate=   0.2kbits/s    
  
  video:620kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  
  Input file #0 (./dataset_test/videos/jz_10_huron_barstow.mkv):
  
    Input stream #0:0 (video): 43323 packets read (347030822 bytes); 43323 frames decoded; 
  
    Input stream #0:1 (audio): 4 packets read (3072 bytes); 
  
    Total: 43327 packets (347033894 bytes) demuxed
  
  Output file #0 (./out/jz_10_huron_barstow/F/0_F.mp4):
  
    Output stream #0:0 (video): 0 frames encoded; 0 packets muxed (0 bytes); 
  
    Total: 0 packets (0 bytes) muxed
  
  Output file #1 (./out/jz_10_huron_barstow/F/1_F.mp4):
  
    Output stream #1:0 (video): 270 frames encoded; 270 packets muxed (309743 bytes); 
  
    Total: 270 packets (309743 bytes) muxed
  
  Output file #2 (./out/jz_10_huron_barstow/L/0_L.mp4):
  
    Output stream #2:0 (video): 270 frames encoded; 270 packets muxed (169687 bytes); 
  
    Total: 270 packets (169687 bytes) muxed
  
  Output file #3 (./out/jz_10_huron_barstow/L/1_L.mp4):
  
    Output stream #3:0 (video): 270 frames encoded; 270 packets muxed (155502 bytes); 
  
    Total: 270 packets (155502 bytes) muxed
  
  [libx264 @ 0x7fdfd400f600] frame I:2     Avg QP:25.08  size:  3204
  
  [libx264 @ 0x7fdfd400f600] frame P:140   Avg QP:26.63  size:  1426
  
  [libx264 @ 0x7fdfd400f600] frame B:128   Avg QP:28.64  size:   805
  
  [libx264 @ 0x7fdfd400f600] consecutive B-frames:  5.2% 94.8%  0.0%  0.0%
  
  [libx264 @ 0x7fdfd400f600] mb I  I16..4:  8.6% 62.7% 28.7%
  
  [libx264 @ 0x7fdfd400f600] mb P  I16..4:  2.5% 12.5%  3.4%  P16..4: 39.2% 21.4%  9.3%  0.0%  0.0%    skip:11.6%
  
  [libx264 @ 0x7fdfd400f600] mb B  I16..4:  0.5%  4.0%  1.0%  B16..8: 36.5% 16.7%  4.0%  direct: 5.5%  skip:31.8%  L0:43.4% L1:46.9% BI: 9.7%
  
  [libx264 @ 0x7fdfd400f600] 8x8 transform intra:68.6% inter:67.7%
  
  [libx264 @ 0x7fdfd400f600] coded y,uvDC,uvAC intra: 63.1% 48.6% 17.9% inter: 34.5% 21.1% 3.6%
  
  [libx264 @ 0x7fdfd400f600] i16 v,h,dc,p: 24% 23% 12% 41%
  
  [libx264 @ 0x7fdfd400f600] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 19% 26%  7%  5%  5%  7%  6%  8%
  
  [libx264 @ 0x7fdfd400f600] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 29% 18%  6%  6%  5%  5%  4%  5%
  
  [libx264 @ 0x7fdfd400f600] i8c dc,h,v,p: 63% 21% 14%  3%
  
  [libx264 @ 0x7fdfd400f600] Weighted P-Frames: Y:14.3% UV:1.4%
  
  [libx264 @ 0x7fdfd400f600] ref P L0: 49.2% 20.4% 17.3% 11.2%  1.9%
  
  [libx264 @ 0x7fdfd400f600] ref B L0: 75.4% 24.6%
  
  [libx264 @ 0x7fdfd400f600] kb/s:274.71
  
  [libx264 @ 0x7fdfd4018e00] frame I:2     Avg QP:23.87  size:  2294
  
  [libx264 @ 0x7fdfd4018e00] frame P:133   Avg QP:25.45  size:   864
  
  [libx264 @ 0x7fdfd4018e00] frame B:135   Avg QP:28.99  size:   367
  
  [libx264 @ 0x7fdfd4018e00] consecutive B-frames: 17.4% 38.5% 27.8% 16.3%
  
  [libx264 @ 0x7fdfd4018e00] mb I  I16..4: 14.5% 54.1% 31.4%
  
  [libx264 @ 0x7fdfd4018e00] mb P  I16..4:  6.4%  9.6%  2.1%  P16..4: 33.3% 16.7%  5.9%  0.0%  0.0%    skip:26.0%
  
  [libx264 @ 0x7fdfd4018e00] mb B  I16..4:  1.6%  2.0%  0.3%  B16..8: 29.6%  9.3%  1.4%  direct: 2.2%  skip:53.6%  L0:41.9% L1:51.4% BI: 6.7%
  
  [libx264 @ 0x7fdfd4018e00] 8x8 transform intra:52.8% inter:73.8%
  
  [libx264 @ 0x7fdfd4018e00] coded y,uvDC,uvAC intra: 40.7% 41.7% 8.9% inter: 20.7% 16.6% 0.2%
  
  [libx264 @ 0x7fdfd4018e00] i16 v,h,dc,p: 22% 50%  8% 21%
  
  [libx264 @ 0x7fdfd4018e00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18% 30% 23%  6%  2%  2%  5%  5%  9%
  
  [libx264 @ 0x7fdfd4018e00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 29% 14%  5%  3%  4%  5%  6%  5%
  
  [libx264 @ 0x7fdfd4018e00] i8c dc,h,v,p: 62% 23% 12%  3%
  
  [libx264 @ 0x7fdfd4018e00] Weighted P-Frames: Y:1.5% UV:0.8%
  
  [libx264 @ 0x7fdfd4018e00] ref P L0: 56.1% 15.8% 17.7% 10.2%  0.1%
  
  [libx264 @ 0x7fdfd4018e00] ref B L0: 75.4% 20.8%  3.9%
  
  [libx264 @ 0x7fdfd4018e00] ref B L1: 92.6%  7.4%
  
  [libx264 @ 0x7fdfd4018e00] kb/s:150.22
  
  [libx264 @ 0x7fdfd4022600] frame I:2     Avg QP:23.86  size:  2208
  
  [libx264 @ 0x7fdfd4022600] frame P:139   Avg QP:24.90  size:   784
  
  [libx264 @ 0x7fdfd4022600] frame B:129   Avg QP:28.25  size:   322
  
  [libx264 @ 0x7fdfd4022600] consecutive B-frames: 17.8% 50.4% 15.6% 16.3%
  
  [libx264 @ 0x7fdfd4022600] mb I  I16..4: 15.7% 53.3% 31.1%
  
  [libx264 @ 0x7fdfd4022600] mb P  I16..4:  8.3%  9.9%  1.5%  P16..4: 33.8% 14.8%  5.0%  0.0%  0.0%    skip:26.7%
  
  [libx264 @ 0x7fdfd4022600] mb B  I16..4:  1.6%  1.8%  0.1%  B16..8: 28.8%  8.2%  1.1%  direct: 2.1%  skip:56.4%  L0:45.5% L1:47.6% BI: 6.9%
  
  [libx264 @ 0x7fdfd4022600] 8x8 transform intra:50.6% inter:75.8%
  
  [libx264 @ 0x7fdfd4022600] coded y,uvDC,uvAC intra: 34.0% 44.3% 10.0% inter: 18.8% 17.9% 0.4%
  
  [libx264 @ 0x7fdfd4022600] i16 v,h,dc,p: 18% 54%  8% 20%
  
  [libx264 @ 0x7fdfd4022600] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 28% 26%  6%  2%  2%  4%  5%  8%
  
  [libx264 @ 0x7fdfd4022600] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 32% 31% 14%  4%  2%  2%  3%  7%  5%
  
  [libx264 @ 0x7fdfd4022600] i8c dc,h,v,p: 60% 25% 13%  2%
  
  [libx264 @ 0x7fdfd4022600] Weighted P-Frames: Y:2.2% UV:0.7%
  
  [libx264 @ 0x7fdfd4022600] ref P L0: 57.9% 16.8% 16.1%  8.9%  0.2%
  
  [libx264 @ 0x7fdfd4022600] ref B L0: 76.5% 21.0%  2.5%
  
  [libx264 @ 0x7fdfd4022600] ref B L1: 95.0%  5.0%
  
  [libx264 @ 0x7fdfd4022600] kb/s:137.61

• Dreamcast SD Adapter and DreamShell

  31 décembre 2014, par Multimedia Mike — Sega Dreamcast

  Nope ! I’m never going to let go of the Sega Dreamcast hacking. When I was playing around with Dreamcast hacking early last year, I became aware that there is such a thing as an SD card adapter for the DC that plugs into the port normally reserved for the odd DC link cable. Of course I wanted to see what I could do with it.

  The primary software that leverages the DC SD adapter is called DreamShell. Working with this adapter and the software requires some skill and guesswork. Searching for these topics tends to turn up results from various forums where people are trying to cargo-cult their way to solutions. I have a strange feeling that this post might become the unofficial English-language documentation on the matter.

  Use Cases
  What can you do with this thing ? Undoubtedly, the primary use is for backing up (ripping) the contents of GD-ROMs (the custom optical format used for the DC) and playing those backed up (ripped) copies. Presumably, users of this device leverage the latter use case more than the former, i.e., download ripped games, load them on the SD card, and launch them using DreamShell.

  However, there are other uses such as multimedia playback, system exploration, BIOS reprogramming, high-level programming, and probably a few other things I haven’t figured out yet.

  Delivery
  I put in an order via the dc-sd.com website and in about 2 short months, the item arrived from China. This marked my third lifetime delivery from China and curiously, all 3 of the shipments have pertained to the Sega Dreamcast.

  
  

  

  Click for larger image

  
  

  I thought it was very interesting that this adapter came in such complete packaging. The text is all in Chinese, though the back states “Windows 98 / ME / 2000 / XP, Mac OS 9.1, LINUX2.4”. That’s what tipped me off that they must have just cannibalized some old USB SD card readers and packaging in order to create these. Closer inspection of the internals through the translucent pink case confirms this.

  Usage
  According to its change log, DreamShell has been around for a long time with version 1.0.0 released in February of 2004. The current version is 4.0.0 RC3. There are several downloads available :

  1. DreamShell 4.0 RC 3 CDI Image
  2. DreamShell 4.0 RC 3 + Boot Loader
  3. DreamShell 4.0 RC 3 + Core CDI image

  Option #2 worked for me. It contains a CDI disc image and the DreamShell files in a directory named DS/.

  Burn the CDI to a CD-R in the normal way you would burn a bootable Dreamcast disc from a CDI image. This is open-ended and left as an exercise to the reader, since there are many procedures depending on platform. On Linux, I used a small script I found once called burncdi-dc.sh.

  Then, copy the contents of the DS/ folder to an SD card. As for filesystem, FAT16 and FAT32 are both known to work. The files in DS/ should land in the root of the SD card ; the folder DS/ should not be in the root.

  Plug the SD card into the DC SD adapter and plug the adapter in the link cable port on the back of the Dreamcast. Then, boot the disc. If it works, you will see this minor corruption of the usual Sega licensing screen :

  
  
  

  Then, there will be a brief white-on-black text screen that explains the booting process :
  

  
  
  

  Then, there will be the main DreamShell logo :

  
  
  

  Finally, you will land on the DreamShell main desktop :

  
  
  

  Skepticism
  At first, I was supremely skeptical of the idea that this SD adapter could perform speedily enough to play games reasonably. This was predicated on the observation that my DC coder’s cable that I used to use for homebrew development could not transfer faster than 115200 bits/second, amounting to about 11 kbytes/sec. I assumed that this was a fundamental limitation of the link port.

  In fact, I ripped a few of my Dreamcast discs over a decade ago and still have those rips lying around. So I copied the ISO image of Resident Evil : Code Veronica — the game I personally played most on the DC — to the SD card (anywhere works) and used the “ISO loader” icon seen on the desktop above to launch the game.

  It works :

  
  
  

  The opening FMV plays at full speed. Everything loads as fast as I remember. I was quite surprised.

  Digression : My assumptions about serial speeds have often been mistaken. 10 years ago, I heard stories about how we would soon be able to watch streaming video on our cell phones. I scoffed because I thought the 56K limitation of dialup modems was some sort of fundamental speed-of-light type of limitation for telephony bandwidth, wired or wireless.

  The desktop menu also includes a ‘speedtest’ tool that profiles the write and read performance of your preferred storage medium. For my fastest SD card (a PNY 2 GB card) :

  
  
  

  This is probably more representative of the true adapter bandwidth as reading and writing is a good deal faster through more modern interfaces on PC and Mac with this same card.

  Look at the other options on the speedtest console. Hard drive ? Apparently, it’s possible, but it requires a good deal more hardware hacking than just purchasing this SD adapter.

  Ripping
  As you can see from the Resident Evil screenshot, playing games works quite nicely. How about ripping ? I’m pleased to say that DreamShell has a beautiful ripping interface :

  
  
  

  Enter a name for the disc (or read the disc label), select the storage medium, and let it, well, rip. It indicates which track it’s working on and the Sega logo acts as a progress bar, shading blue as the track rip progresses.

  I’m finally, efficiently, archiving that collection of Sega Dreamcast demo discs ; I’m hoping they’ll eventually find a home at the Internet Archive. How is overall ripping performance ? Usually about 38-40 minutes to rip a full 900-1000 MB. That certainly beats the 27-28 hours that were required when I performed the ripping at 11 kbytes/sec via the DC coders cable.

  All is well until I get a sector reading error :

  
  
  

  That’s when it can come in handy to have 3 DC consoles (see ?! not crazy !).

  Other Uses
  There’s a file explorer. You can browse the filesystem of the SD card, visual memory unit, or the CD portion of the GD-ROM (would be more useful if it accessed the GD area). There are FFmpeg files included. So I threw a random Cinepak file and random MPEG-1 file at it to see what happens. MPEG-1 didn’t do anything, but this Cinepak file from some Sierra game played handily :

  
  
  

  If you must enter strings, it helps to have a Dreamcast keyboard (which I do). Failing that, here’s a glimpse of the onscreen keyboard that DreamShell equips :

  
  
  

  Learning to use it is a game in itself.

  There is an option of installing DreamShell in the BIOS. I did not attempt this. I don’t know if it’s possible (not like there’s a lot of documentation)– perhaps a custom BIOS modchip is needed. But here’s what the screen looks like :

  
  
  

  There is also a plain console to interact with (better have a physical keyboard). There are numerous file manipulation commands and custom system interaction commands. I see one interesting command called ‘addr’ that looks useful for dumping memory regions to a file.

  A Lua language interpreter is also built in. I would love to play with this if I could ascertain whether DreamShell provided Dreamcast-specific APIs.

  Tips And Troubleshooting
  I have 3 Dreamcast consoles, affectionately named Terran, Protoss, and Zerg after the StarCraft II stickers with which they are adorned. Some seem to work better than others. Protoss seemed to be able to boot the DreamShell disc more reliably than the others. However, I was alarmed when it couldn’t boot one morning when it was churning the previous day.

  I think the problem is that it was just cold. That seemed to be the issue. I put in a normal GD-ROM and let it warm up on that disc for awhile and then DreamShell booted fine. So that’s my piece of cargo-culting troubleshooting advice.

• Dreamcast SD Adapter and DreamShell

  31 décembre 2014, par Multimedia Mike — Sega Dreamcast

  Nope ! I’m never going to let go of the Sega Dreamcast hacking. When I was playing around with Dreamcast hacking early last year, I became aware that there is such a thing as an SD card adapter for the DC that plugs into the port normally reserved for the odd DC link cable. Of course I wanted to see what I could do with it.

  The primary software that leverages the DC SD adapter is called DreamShell. Working with this adapter and the software requires some skill and guesswork. Searching for these topics tends to turn up results from various forums where people are trying to cargo-cult their way to solutions. I have a strange feeling that this post might become the unofficial English-language documentation on the matter.

  Use Cases
  What can you do with this thing ? Undoubtedly, the primary use is for backing up (ripping) the contents of GD-ROMs (the custom optical format used for the DC) and playing those backed up (ripped) copies. Presumably, users of this device leverage the latter use case more than the former, i.e., download ripped games, load them on the SD card, and launch them using DreamShell.

  However, there are other uses such as multimedia playback, system exploration, BIOS reprogramming, high-level programming, and probably a few other things I haven’t figured out yet.

  Delivery
  I put in an order via the dc-sd.com website and in about 2 short months, the item arrived from China. This marked my third lifetime delivery from China and curiously, all 3 of the shipments have pertained to the Sega Dreamcast.

  
  

  

  Click for larger image

  
  

  I thought it was very interesting that this adapter came in such complete packaging. The text is all in Chinese, though the back states “Windows 98 / ME / 2000 / XP, Mac OS 9.1, LINUX2.4”. That’s what tipped me off that they must have just cannibalized some old USB SD card readers and packaging in order to create these. Closer inspection of the internals through the translucent pink case confirms this.

  Usage
  According to its change log, DreamShell has been around for a long time with version 1.0.0 released in February of 2004. The current version is 4.0.0 RC3. There are several downloads available :

  1. DreamShell 4.0 RC 3 CDI Image
  2. DreamShell 4.0 RC 3 + Boot Loader
  3. DreamShell 4.0 RC 3 + Core CDI image

  Option #2 worked for me. It contains a CDI disc image and the DreamShell files in a directory named DS/.

  Burn the CDI to a CD-R in the normal way you would burn a bootable Dreamcast disc from a CDI image. This is open-ended and left as an exercise to the reader, since there are many procedures depending on platform. On Linux, I used a small script I found once called burncdi-dc.sh.

  Then, copy the contents of the DS/ folder to an SD card. As for filesystem, FAT16 and FAT32 are both known to work. The files in DS/ should land in the root of the SD card ; the folder DS/ should not be in the root.

  Plug the SD card into the DC SD adapter and plug the adapter in the link cable port on the back of the Dreamcast. Then, boot the disc. If it works, you will see this minor corruption of the usual Sega licensing screen :

  
  
  

  Then, there will be a brief white-on-black text screen that explains the booting process :
  

  
  
  

  Then, there will be the main DreamShell logo :

  
  
  

  Finally, you will land on the DreamShell main desktop :

  
  
  

  Skepticism
  At first, I was supremely skeptical of the idea that this SD adapter could perform speedily enough to play games reasonably. This was predicated on the observation that my DC coder’s cable that I used to use for homebrew development could not transfer faster than 115200 bits/second, amounting to about 11 kbytes/sec. I assumed that this was a fundamental limitation of the link port.

  In fact, I ripped a few of my Dreamcast discs over a decade ago and still have those rips lying around. So I copied the ISO image of Resident Evil : Code Veronica — the game I personally played most on the DC — to the SD card (anywhere works) and used the “ISO loader” icon seen on the desktop above to launch the game.

  It works :

  
  
  

  The opening FMV plays at full speed. Everything loads as fast as I remember. I was quite surprised.

  Digression : My assumptions about serial speeds have often been mistaken. 10 years ago, I heard stories about how we would soon be able to watch streaming video on our cell phones. I scoffed because I thought the 56K limitation of dialup modems was some sort of fundamental speed-of-light type of limitation for telephony bandwidth, wired or wireless.

  The desktop menu also includes a ‘speedtest’ tool that profiles the write and read performance of your preferred storage medium. For my fastest SD card (a PNY 2 GB card) :

  
  
  

  This is probably more representative of the true adapter bandwidth as reading and writing is a good deal faster through more modern interfaces on PC and Mac with this same card.

  Look at the other options on the speedtest console. Hard drive ? Apparently, it’s possible, but it requires a good deal more hardware hacking than just purchasing this SD adapter.

  Ripping
  As you can see from the Resident Evil screenshot, playing games works quite nicely. How about ripping ? I’m pleased to say that DreamShell has a beautiful ripping interface :

  
  
  

  Enter a name for the disc (or read the disc label), select the storage medium, and let it, well, rip. It indicates which track it’s working on and the Sega logo acts as a progress bar, shading blue as the track rip progresses.

  I’m finally, efficiently, archiving that collection of Sega Dreamcast demo discs ; I’m hoping they’ll eventually find a home at the Internet Archive. How is overall ripping performance ? Usually about 38-40 minutes to rip a full 900-1000 MB. That certainly beats the 27-28 hours that were required when I performed the ripping at 11 kbytes/sec via the DC coders cable.

  All is well until I get a sector reading error :

  
  
  

  That’s when it can come in handy to have 3 DC consoles (see ?! not crazy !).

  Other Uses
  There’s a file explorer. You can browse the filesystem of the SD card, visual memory unit, or the CD portion of the GD-ROM (would be more useful if it accessed the GD area). There are FFmpeg files included. So I threw a random Cinepak file and random MPEG-1 file at it to see what happens. MPEG-1 didn’t do anything, but this Cinepak file from some Sierra game played handily :

  
  
  

  If you must enter strings, it helps to have a Dreamcast keyboard (which I do). Failing that, here’s a glimpse of the onscreen keyboard that DreamShell equips :

  
  
  

  Learning to use it is a game in itself.

  There is an option of installing DreamShell in the BIOS. I did not attempt this. I don’t know if it’s possible (not like there’s a lot of documentation)– perhaps a custom BIOS modchip is needed. But here’s what the screen looks like :

  
  
  

  There is also a plain console to interact with (better have a physical keyboard). There are numerous file manipulation commands and custom system interaction commands. I see one interesting command called ‘addr’ that looks useful for dumping memory regions to a file.

  A Lua language interpreter is also built in. I would love to play with this if I could ascertain whether DreamShell provided Dreamcast-specific APIs.

  Tips And Troubleshooting
  I have 3 Dreamcast consoles, affectionately named Terran, Protoss, and Zerg after the StarCraft II stickers with which they are adorned. Some seem to work better than others. Protoss seemed to be able to boot the DreamShell disc more reliably than the others. However, I was alarmed when it couldn’t boot one morning when it was churning the previous day.

  I think the problem is that it was just cold. That seemed to be the issue. I put in a normal GD-ROM and let it warm up on that disc for awhile and then DreamShell booted fine. So that’s my piece of cargo-culting troubleshooting advice.