uint8_t *buf = (uint8_t *)av_malloc(MUX_BUFFER_SIZE);
avctx->pb = avio_alloc_context(buf, MUX_BUFFER_SIZE, 1, this, nullptr, nullptr, nullptr);
uint8_t *buf = (uint8_t *)av_malloc(MUX_BUFFER_SIZE);
avctx->pb = avio_alloc_context(buf, MUX_BUFFER_SIZE, 1, this, nullptr, nullptr, nullptr);