<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">I have an MXF Op1b file (which I can’t share due to a strict NDA) using the AVC codec which I’d like to playback in my app.<div class="">When opening the file with libavformat, it gets recognized and it plays back just fine at first.</div><div class="">However, the playback gets stuck after a couple of seconds.</div><div class=""><br class=""></div><div class="">I found out that there’s an issue with the index tables and partitions within the MXF file.</div><div class="">I don’t remember the exact position but there was an annotation in the code that currently only Op1a and OpAtom files are handled properly.</div><div class=""><br class=""></div><div class="">As the decoding seems to work fine using libavcodec, I’d like to use only the decoder part and gather the AVPackets myself using code I already have based on the open source MXF Lib.</div><div class="">While this approach does work in general, the H.264 decoder gives me a lot of errors during decoding like:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x1059fda00] concealing 50 DC, 50 AC, 50 MV errors in I frame</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b29600] concealing 50 DC, 50 AC, 50 MV errors in I frame</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b37600] negative number of zero coeffs at 255 134</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b37600] error while decoding MB 255 134</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b37600] concealing 50 DC, 50 AC, 50 MV errors in I frame</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b2a800] concealing 2048 DC, 2048 AC, 2048 MV errors in I frame</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b2ae00] negative number of zero coeffs at 255 134</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b2ae00] error while decoding MB 255 134</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b2ae00] concealing 50 DC, 50 AC, 50 MV errors in I frame</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b43c00] concealing 2048 DC, 2048 AC, 2048 MV errors in I frame</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b44200] corrupted macroblock 254 134 (total_coeff=-1)</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b44200] error while decoding MB 254 134</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b44200] concealing 51 DC, 51 AC, 51 MV errors in I frame</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b44800] negative number of zero coeffs at 254 134</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b44800] error while decoding MB 254 134</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b44800] concealing 51 DC, 51 AC, 51 MV errors in I frame</b></div><div style="margin: 0px; font-size: 11px; font-family: Menlo;" class=""><b class="">[h264 @ 0x105b44e00] concealing 2048 DC, 2048 AC, 2048 MV errors in I frame</b></div></div><div class=""><br class=""></div><div class="">The first error occurs when the frameFinished flag of av_decode_video2 is true for the first time.</div><div class="">The image itself looks fine but there are some areas with pink and white bar-like artifacts.</div><div class=""><br class=""></div><div class="">It was my understanding that avformat provides data packets only.</div><div class="">However, this looks to me like it also adjusts parameters of the AVCodecContext during reading?</div><div class=""><br class=""></div><div class="">Any pointers as to how I could make the decoder happy would be highly appreciated.</div><div class=""><br class=""></div><div class="">Thanks,</div><div class=""><br class=""></div><div class="">best,</div><div class=""><br class=""></div><div class="">Flo</div></body></html>