v = av_crc(av_crc_get_table(AV_CRC_32_IEEE), 0, f->avctx->extradata, f->avctx->extradata_size);
AV_WL32(f->avctx->extradata + f->avctx->extradata_size, v);
f->avctx->extradata_size += 4;
v = av_crc(av_crc_get_table(AV_CRC_32_IEEE), 0, f->avctx->extradata, f->avctx->extradata_size);
AV_WL32(f->avctx->extradata + f->avctx->extradata_size, v);
f->avctx->extradata_size += 4;