static int read_interval_packets(WriterContext *w, AVFormatContext *fmt_ctx, const ReadInterval *interval, int64_t *cur_ts) { AVPacket pkt, pkt1; AVFrame *frame = NULL; int ret = 0, i = 0, frame_count = 0; int64_t start = -INT64_MAX, end = interval->end; int has_start = 0, has_end = interval->has_end && !interval->end_is_offset; av_init_packet(&pkt); av_log(NULL, AV_LOG_VERBOSE, "Processing read interval "); log_read_interval(interval, NULL, AV_LOG_VERBOSE); if (interval->has_start) { int64_t target; if (interval->start_is_offset) { if (*cur_ts == AV_NOPTS_VALUE) { av_log(NULL, AV_LOG_ERROR, "Could not seek to relative position since current " "timestamp is not defined\n"); ret = AVERROR(EINVAL); target = *cur_ts + interval->start; } else { target = interval->start; av_log(NULL, AV_LOG_VERBOSE, "Seeking to read interval start point %s\n", av_ts2timestr(target, &AV_TIME_BASE_Q)); if ((ret = avformat_seek_file(fmt_ctx, -1, -INT64_MAX, target, INT64_MAX, 0)) < 0) { av_log(NULL, AV_LOG_ERROR, "Could not seek to position %"PRId64": %s\n", interval->start, av_err2str(ret)); frame = av_frame_alloc(); while (!av_read_frame(fmt_ctx, &pkt)) { if (selected_streams[pkt.stream_index]) { AVRational tb = fmt_ctx->streams[pkt.stream_index]->time_base; if (pkt.pts != AV_NOPTS_VALUE) *cur_ts = av_rescale_q(pkt.pts, tb, AV_TIME_BASE_Q); if (!has_start && *cur_ts != AV_NOPTS_VALUE) { start = *cur_ts; has_start = 1; if (has_start && !has_end && interval->end_is_offset) { end = start + interval->end; has_end = 1; if (interval->end_is_offset && interval->duration_frames) { if (frame_count >= interval->end) break; } else if (has_end && *cur_ts != AV_NOPTS_VALUE && *cur_ts >= end) { break; frame_count++; if (do_read_packets) { if (do_show_packets) show_packet(w, fmt_ctx, &pkt, i++); nb_streams_packets[pkt.stream_index]++; if (do_read_frames) { pkt1 = pkt; while (pkt1.size && process_frame(w, fmt_ctx, frame, &pkt1) > 0); av_free_packet(&pkt); av_init_packet(&pkt); pkt.data = NULL; pkt.size = 0; //Flush remaining frames that are cached in the decoder for (i = 0; i < fmt_ctx->nb_streams; i++) { pkt.stream_index = i; if (do_read_frames) while (process_frame(w, fmt_ctx, frame, &pkt) > 0); end: av_frame_free(&frame); if (ret < 0) { av_log(NULL, AV_LOG_ERROR, "Could not read packets in interval "); log_read_interval(interval, NULL, AV_LOG_ERROR); return ret;