76     AVFrame *last_frame;  member
774                 ret = av_frame_copy(diffFrame, s->last_frame);  in apng_encode_frame()
889     } else if (s->last_frame) {  in encode_apng()
896         pkt->pts = pkt->dts = s->last_frame->pts;  in encode_apng()
920     if (s->last_frame) {  in encode_apng()
946         if (!s->last_frame) {  in encode_apng()
947             s->last_frame = av_frame_alloc();  in encode_apng()
948             if (!s->last_frame)  in encode_apng()
964             av_frame_copy(s->prev_frame, s->last_frame);  in encode_apng()
975         av_frame_unref(s->last_frame);  in encode_apng()
976         ret = av_frame_ref(s->last_frame, (AVFrame*)pict);  in encode_apng()
983         av_frame_free(&s->last_frame);  in encode_apng()
1103     av_frame_free(&s->last_frame);  in png_enc_close()