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| ret = avformat_write_header(ofmt_ctx, NULL); if (ret < 0) { fprintf(stderr, "Error occurred when opening output file\n"); goto end; }
ret = av_seek_frame(ifmt_ctx, -1, start_seconds * AV_TIME_BASE, AVSEEK_FLAG_ANY); if (ret < 0) { fprintf(stderr, "Error seek\n"); goto end; }
int64_t *dts_start_from = malloc(sizeof(int64_t) * ifmt_ctx->nb_streams); memset(dts_start_from, 0, sizeof(int64_t) * ifmt_ctx->nb_streams);
int64_t *pts_start_from = malloc(sizeof(int64_t) * ifmt_ctx->nb_streams); memset(pts_start_from, 0, sizeof(int64_t) * ifmt_ctx->nb_streams);
while (1) { AVStream *in_stream, *out_stream;
ret = av_read_frame(ifmt_ctx, &pkt); if (ret < 0) break;
in_stream = ifmt_ctx->streams[pkt.stream_index]; out_stream = ofmt_ctx->streams[pkt.stream_index];
if (av_q2d(in_stream->time_base) * pkt.pts > end_seconds) { av_packet_unref(&pkt); break; }
if (dts_start_from[pkt.stream_index] == 0) { dts_start_from[pkt.stream_index] = pkt.dts; } if (pts_start_from[pkt.stream_index] == 0) { pts_start_from[pkt.stream_index] = pkt.pts; }
pkt.pts = av_rescale_q_rnd(pkt.pts - pts_start_from[pkt.stream_index], in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX); pkt.dts = av_rescale_q_rnd(pkt.dts - dts_start_from[pkt.stream_index], in_stream->time_base,out_stream->time_base, AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX); if (pkt.pts < 0) { pkt.pts = 0; } if (pkt.dts < 0) { pkt.dts = 0; }
pkt.duration = (int) av_rescale_q((int64_t) pkt.duration, in_stream->time_base, out_stream->time_base); pkt.pos = -1;
if (pkt.pts < pkt.dts) { continue; } ret = av_interleaved_write_frame(ofmt_ctx, &pkt); if (ret < 0) { fprintf(stderr, "Error write packet\n"); break; }
av_packet_unref(&pkt); }
free(dts_start_from); free(pts_start_from);
av_write_trailer(ofmt_ctx);
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