And not just the first, as it was being done for lacing. The spec states that the flag applies to everything inside the simple box.
Unified · Split
| @@ -4224,7 +4224,7 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, AVBufferRef *buf · 4223 unmodified lines | ||
| 4224 | 4224 | } else { |
| 4225 | 4225 | res = matroska_parse_frame(matroska, track, st, buf, out_data, |
| 4226 | 4226 | out_size, timecode, lace_duration, |
| 4227 | − pos, !n ? is_keyframe : 0, | |
| 4227 | + pos, is_keyframe, | |
| 4228 | 4228 | blockmore, nb_blockmore, |
| 4229 | 4229 | discard_padding); |
| 4230 | 4230 | if (res) |