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 Question:

Raspbmc video freezes at certain points during Mp4 playback
  • John Leehey

    Im trying to play an Mp4 with raspbmc, but the video keeps freezing. The funny thing is that it always freezes at the same points of the file. When it freezes, the audio is still played, and i can skip forward then back, and it will regain the image and be fine. It happens fairly often though. Is this a known issue, and can it be fixed?

    Update: here is the mediainfo text layout:

    General
    Complete name                            : F:\tv_show.mp4
    Format                                   : MPEG-4
    Format profile                           : Base Media
    Codec ID                                 : isom
    File size                                : 391 MiB
    Duration                                 : 53mn 55s
    Overall bit rate mode                    : Variable
    Overall bit rate                         : 1 015 Kbps
    Encoded date                             : UTC 2011-09-08 11:43:25
    Tagged date                              : UTC 2011-09-08 11:43:25
    
    Video
    ID                                       : 1
    Format                                   : AVC
    Format/Info                              : Advanced Video Codec
    Format profile                           : [email protected]
    Format settings, CABAC                   : Yes
    Format settings, ReFrames                : 5 frames
    Codec ID                                 : avc1
    Codec ID/Info                            : Advanced Video Coding
    Duration                                 : 53mn 55s
    Bit rate                                 : 877 Kbps
    Width                                    : 720 pixels
    Height                                   : 402 pixels
    Display aspect ratio                     : 16:9
    Frame rate mode                          : Constant
    Frame rate                               : 23.976 fps
    Color space                              : YUV
    Chroma subsampling                       : 4:2:0
    Bit depth                                : 8 bits
    Scan type                                : Progressive
    Bits/(Pixel*Frame)                       : 0.126
    Stream size                              : 338 MiB (86%)
    Writing library                          : x264 core 128 r2216 198a7ea
    Encoding settings                        : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=8 / 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=18 / lookahead_threads=3 / 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=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=19.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
    Encoded date                             : UTC 2011-09-08 11:43:25
    Tagged date                              : UTC 2011-09-08 11:43:25
    Matrix coefficients                      : BT.709
    
    Audio
    ID                                       : 2
    Format                                   : AAC
    Format/Info                              : Advanced Audio Codec
    Format profile                           : LC
    Codec ID                                 : 40
    Duration                                 : 53mn 55s
    Bit rate mode                            : Variable
    Bit rate                                 : 132 Kbps
    Maximum bit rate                         : 229 Kbps
    Channel(s)                               : 2 channels
    Channel positions                        : Front: L R
    Sampling rate                            : 48.0 KHz
    Compression mode                         : Lossy
    Delay relative to video                  : 83ms
    Stream size                              : 50.8 MiB (13%)
    Encoded date                             : UTC 2011-09-08 11:43:25
    Tagged date                              : UTC 2011-09-08 11:43:25
    
  •  Answers:

  • Morgan

    There are several reasons a video could freeze:

    • The player/device cannot handle high bitrate videos. But as I mentionned in the question comments, I already played a 40 Mbps mkv video and your video has a bitrate of 1015 Kbps (~ 1 Mbps).
    • The source (SD card, USB flash drive, network, etc.) is to slow to manage a 1-Mbps stream. Sounds weird, but possible.
    • The video has ASS/SSA styled subtitles. I had some problems with this kind of video. When the subtitles are disabled, the video is played smoothly (CPU is ~ 50 % busy). But when they are enabled, the CPU is fully loaded, and the player chokes.