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  1. for example I downloaded some film, it is somehow encoded with some program, when I try to use ffmpeg to convert it, let's say from mkv to mp4, i get an error that:

    [matroska,webm @ 0x1d06640] Read error at pos. 2241497 (0x2233d9)

    now how can I know where is the reason that this happens? should just avoid this kind of files, or somehow debug it and see what is the reason behind this error? or maybe skip this error frames, but i dont know how many frames may be like this, what if most of the file is filled with corrupted frames, altough it is playable in the video player
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  2. You can try to force ffmpeg to ignore errors - add bellow to your commandline
    Code:
    -err_detect ignore_err -ec guess_mvs+deblock+favor_inter -ignore_unknown
    I would advise to reencode your source so output will have corrupted content but will be correct from syntax perspective.
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  3. Originally Posted by pandy View Post
    You can try to force ffmpeg to ignore errors - add bellow to your commandline
    Code:
    -err_detect ignore_err -ec guess_mvs+deblock+favor_inter -ignore_unknown
    I would advise to reencode your source so output will have corrupted content but will be correct from syntax perspective.
    after trying this commands:

    Code:
    [matroska,webm @ 0x1789580] Read error at pos. 2241497 (0x2233d9)
    [h264 @ 0x28aaee0] error while decoding MB 45 33, bytestream -11
    [h264 @ 0x28aaee0] concealing 964 DC, 964 AC, 964 MV errors in B frame
    frame=  191 fps= 18 q=-1.0 Lsize=     934kB time=00:43:40.12 bitrate=   2.9kbits/s    
    video:558kB audio:372kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.478487%
    [libx264 @ 0x17d5720] frame I:3     Avg QP:14.47  size:  8780
    [libx264 @ 0x17d5720] frame P:99    Avg QP:17.68  size:  5154
    [libx264 @ 0x17d5720] frame B:89    Avg QP:14.18  size:   381
    [libx264 @ 0x17d5720] consecutive B-frames: 33.0% 14.7%  0.0% 52.4%
    [libx264 @ 0x17d5720] mb I  I16..4: 51.4% 44.1%  4.5%
    [libx264 @ 0x17d5720] mb P  I16..4:  2.9%  6.8%  0.1%  P16..4: 23.0%  3.1%  3.1%  0.0%  0.0%    skip:61.0%
    [libx264 @ 0x17d5720] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  5.0%  0.1%  0.0%  direct: 0.1%  skip:94.7%  L0:39.8% L1:58.6% BI: 1.6%
    [libx264 @ 0x17d5720] 8x8 transform intra:63.4% inter:85.2%
    [libx264 @ 0x17d5720] coded y,uvDC,uvAC intra: 20.2% 24.4% 4.2% inter: 5.0% 6.7% 0.2%
    [libx264 @ 0x17d5720] i16 v,h,dc,p: 59% 20% 10% 11%
    [libx264 @ 0x17d5720] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 24% 13% 53%  2%  2%  2%  2%  1%  1%
    [libx264 @ 0x17d5720] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 40% 19% 22%  4%  5%  3%  4%  2%  2%
    [libx264 @ 0x17d5720] i8c dc,h,v,p: 80% 10%  9%  0%
    [libx264 @ 0x17d5720] Weighted P-Frames: Y:21.2% UV:18.2%
    [libx264 @ 0x17d5720] ref P L0: 56.8% 13.1% 20.7%  8.4%  1.1%
    [libx264 @ 0x17d5720] ref B L0: 79.9% 17.9%  2.2%
    [libx264 @ 0x17d5720] kb/s:1.74
    after converting the output video, the file size is too low and it just stops while playing at some point and thats it,

    I've tried to reencode it to the same container mkv, but got the same errors

    tried to reencode wit this command:

    Code:
    ffmpeg -err_detect ignore_err -ec guess_mvs+deblock+favor_inter -i "film.mkv" -c:v libx265 -preset ultrafast -x265-params lossless=1 test.mkv
    output:

    Code:
    [matroska,webm @ 0x1e94ba0] Read error at pos. 2241497 (0x2233d9)
    [h264 @ 0x2853500] error while decoding MB 45 33, bytestream -11
    [h264 @ 0x2853500] concealing 964 DC, 964 AC, 964 MV errors in B frame
    [matroska @ 0x1efe6c0] Starting new cluster due to timestampitrate=   0.2kbits/s    
    frame=  191 fps= 17 q=0.0 Lsize=   18850kB time=00:43:40.11 bitrate=  58.9kbits/s    
    video:18664kB audio:172kB subtitle:0kB other streams:0kB global headers:8kB muxing overhead: 0.074325%
    x265 [info]: frame I:      1, Avg QP:4.00  kb/s: 230.17  
    x265 [info]: frame P:     48, Avg QP:4.00  kb/s: 21305.16
    x265 [info]: frame B:    142, Avg QP:4.00  kb/s: 18611.59
    x265 [info]: consecutive B-frames: 2.0% 2.0% 0.0% 95.9% 
    x265 [info]: lossless compression ratio 9.21::1
    encoded 191 frames in 11.48s (16.63 fps), 19192.27 kb/s, Avg QP:4.00

    how should I correctly reencode it?, cause even ignoring errors wouldn't help

    video source info by the way:

    Code:
    Video
    ID                             : 1
    Format                         : AVC
    Format/Info                    : Advanced Video Codec
    Format profile                 : High@L3.1
    Format settings, CABAC         : Yes
    Format settings, ReFrames      : 5 frames
    Codec ID                       : V_MPEG4/ISO/AVC
    Bit rate                       : 4 000 Kbps
    Width                          : 1 280 pixels
    Height                         : 720 pixels
    Display aspect ratio           : 16:9
    Frame rate                     : 23,976 fps
    Color space                    : YUV
    Chroma subsampling             : 4:2:0
    Bit depth                      : 8 bits
    Scan type                      : Progressive
    Writing library                : x264 core 148 r2721
    Encoding settings              : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x132 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / 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=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=239 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=abr / mbtree=1 / bitrate=4000 / ratetol=1.0 / qcomp=0.60 / qpmin=5 / qpmax=69 / qpstep=4 / vbv_maxrate=8000 / vbv_bufsize=17500 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=3:1.00
    Default                        : Yes
    Forced                         : No
    Color range                    : Limited
    Color primaries                : BT.709
    Transfer characteristics       : BT.709
    Matrix coefficients            : BT.709
    DURATION                       : 00:44:08.693000000
    Last edited by blurry; 15th Jan 2018 at 01:05.
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  4. It look to me like corrupted storage or seriously corrupted file, beyond listed position ffmpeg is unable to find any useful data...
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  5. Member
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    IMHO, quite obviously your video source is defect, and ffmpeg is unable to decode beyond this point, so it seems to be a larger corruption.

    Different decoders have a different "error resilience"; if ffmpeg can't skip the corrupt part safely, maybe other applications (VLC player - yes, it can convert too; Avidemux) or some AviSynth decoders can (FFMS2, L-SMASH Works, DSS2Mod with LAV Filters, and DirectShowSource as the last hope).
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  6. Member T-dawg's Avatar
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    I was using Handbrake and Format Factory back in a day for that. You can also try WALTR if you wanna watch the movie on Apple devices.
    Life isn't about finding yourself. Life is about creating yourself.
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  7. Member
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    Please note the warning that Format Factory may mess up your system by installing "Possibly Unwanted Programs" (ad-supported freeware).
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