<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=""><div class="">Hi, we encode videos captured in realtime into h264 using ffmpeg’s libav. However, we sometimes see weird grey artifacts covering the whole frame. These artifacts cover up the video until the arrival of the next I-frame. Attached below is a frame printout of one the affected videos. Please note the gap in “coded_picture_number”. It jumps from 0 to 2. There seems to be a correlation between the grey artifacts appearing and gaps in the sequence of “coded_picture_number”, as videos that don’t have gaps play back fine.</div><div class=""><br class=""></div><div class="">The artifacts do not appear when using Quicktime to play back the video. However they do appear when I play back the video using VLC or when transcoding it using ffmpeg cli.</div><div class=""><br class=""></div><div class="">Can a gap in coded_picture_number be indicative to a mistake we’re making during the encoding?</div><div class=""><br class=""></div><div class="">Screenshot of the artifacts: <a href="https://www.dropbox.com/s/fk0wa9fa3cj8ef7/Screen%20Shot%202015-11-24%20at%2015.13.17.png?dl=0" class="">https://www.dropbox.com/s/fk0wa9fa3cj8ef7/Screen%20Shot%202015-11-24%20at%2015.13.17.png?dl=0</a></div><div class=""><br class=""></div><div class="">ffprobe -show_frames -print_format json -select_streams v file.mp4</div><div class=""><br class=""></div><div class=""><div class="">"frames": [</div><div class=""> {</div><div class=""> "media_type": "video",</div><div class=""> "stream_index": 1,</div><div class=""> "key_frame": 1,</div><div class=""> "pkt_pts": 768,</div><div class=""> "pkt_pts_time": "0.040000",</div><div class=""> "pkt_dts": 768,</div><div class=""> "pkt_dts_time": "0.040000",</div><div class=""> "best_effort_timestamp": 768,</div><div class=""> "best_effort_timestamp_time": "0.040000",</div><div class=""> "pkt_duration": 960,</div><div class=""> "pkt_duration_time": "0.050000",</div><div class=""> "pkt_pos": "380",</div><div class=""> "pkt_size": "238171",</div><div class=""> "width": 1024,</div><div class=""> "height": 768,</div><div class=""> "pix_fmt": "yuv420p",</div><div class=""> "pict_type": "I",</div><div class=""> "coded_picture_number": 0,</div><div class=""> "display_picture_number": 0,</div><div class=""> "interlaced_frame": 0,</div><div class=""> "top_field_first": 0,</div><div class=""> "repeat_pict": 0</div><div class=""> },</div><div class=""> {</div><div class=""> "media_type": "video",</div><div class=""> "stream_index": 1,</div><div class=""> "key_frame": 0,</div><div class=""> "pkt_pts": 1728,</div><div class=""> "pkt_pts_time": "0.090000",</div><div class=""> "pkt_dts": 1728,</div><div class=""> "pkt_dts_time": "0.090000",</div><div class=""> "best_effort_timestamp": 1728,</div><div class=""> "best_effort_timestamp_time": "0.090000",</div><div class=""> "pkt_duration": 768,</div><div class=""> "pkt_duration_time": "0.040000",</div><div class=""> "pkt_pos": "238943",</div><div class=""> "pkt_size": "231",</div><div class=""> "width": 1024,</div><div class=""> "height": 768,</div><div class=""> "pix_fmt": "yuv420p",</div><div class=""> "pict_type": "P",</div><div class=""> "coded_picture_number": 2,</div><div class=""> "display_picture_number": 0,</div><div class=""> "interlaced_frame": 0,</div><div class=""> "top_field_first": 0,</div><div class=""> "repeat_pict": 0</div><div class=""> },</div><div class=""> {</div><div class=""> "media_type": "video",</div><div class=""> "stream_index": 1,</div><div class=""> "key_frame": 0,</div><div class=""> "pkt_pts": 2496,</div><div class=""> "pkt_pts_time": "0.130000",</div><div class=""> "pkt_dts": 2496,</div><div class=""> "pkt_dts_time": "0.130000",</div><div class=""> "best_effort_timestamp": 2496,</div><div class=""> "best_effort_timestamp_time": "0.130000",</div><div class=""> "pkt_duration": 384,</div><div class=""> "pkt_duration_time": "0.020000",</div><div class=""> "pkt_pos": "239580",</div><div class=""> "pkt_size": "214",</div><div class=""> "width": 1024,</div><div class=""> "height": 768,</div><div class=""> "pix_fmt": "yuv420p",</div><div class=""> "pict_type": "P",</div><div class=""> "coded_picture_number": 3,</div><div class=""> "display_picture_number": 0,</div><div class=""> "interlaced_frame": 0,</div><div class=""> "top_field_first": 0,</div><div class=""> "repeat_pict": 0</div><div class=""> },</div></div><div class=""><br class=""></div><div class="">[…]</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px;"><div class="" style="margin: 0cm 0cm 0.0001pt;"><font class="Apple-style-span" color="#646464" face="Arial, sans-serif"><span class="Apple-style-span" style="font-size: 11px;">Marvin Killing<br class=""></span></font><span class="" style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(100, 100, 100);">Co-Founder</span></div><p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;"><span class="" style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(100, 100, 100);"> </span></p></span><b class="" style="orphans: 2; widows: 2;"><span class="" style="font-size: 9pt; font-family: Arial;"><font color="#36a0ce" class="">Playtest</font></span><span class="" style="color: rgb(43, 171, 110); font-size: 9pt; font-family: Arial;">Cloud</span></b><br class="" style="orphans: 2; widows: 2;"><span class="Apple-style-span" style="orphans: 2; widows: 2; border-collapse: separate; border-spacing: 0px;"><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px;"><div class="" style="margin: 0cm 0cm 0.0001pt;"><span class="" style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(100, 100, 100);">Rudolf-Breitscheid-Str. 209</span></div><div class="" style="font-family: Calibri, sans-serif; margin: 0cm 0cm 0.0001pt; font-size: 11pt;"><span class="" style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(100, 100, 100);">14482 Potsdam</span></div><div class="" style="font-family: Calibri, sans-serif; margin: 0cm 0cm 0.0001pt; font-size: 11pt;"><span class="" style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(100, 100, 100);">Germany</span></div><div class="" style="font-family: Calibri, sans-serif; margin: 0cm 0cm 0.0001pt; font-size: 11pt;"><span class="" style="font-size: 8pt; font-family: Arial, sans-serif; color: rgb(100, 100, 100);"><br class="">T: +49 151 23068772<br class=""></span></div><div class="" style="font-family: Calibri, sans-serif; margin: 0cm 0cm 0.0001pt; font-size: 11pt;"><br class=""></div><div class="" style="margin: 0cm 0cm 0.0001pt;"><font color="#646464" face="Arial, sans-serif" class=""><span class="" style="font-size: 11px;"><a href="http://www.playtestcloud.com" class="">www.playtestcloud.com</a></span></font></div></span></span><span class="Apple-style-span" style="orphans: 2; widows: 2; border-collapse: separate; border-spacing: 0px;"><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px;"><div class="" style="margin: 0cm 0cm 0.0001pt;"><br class=""><b class="" style="font-family: Calibri, sans-serif; font-size: 11pt;"><span class="" style="font-size: 8pt; font-family: Arial, sans-serif; color: rgb(100, 100, 100);">PlaytestCloud GmbH<br class=""></span></b></div><div class="" style="margin: 0cm 0cm 0.0001pt;"><span class="" style="font-size: 7.5pt; font-family: Arial, sans-serif; color: rgb(100, 100, 100);">Managing Directors: Christian Ress, Marvin Killing</span></div></span></span></div></div></div>
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